In about three weeks, the ACCs regular season will be over. In about four weeks, so will the ACC tournament. You know the old saying: seems like yesterday N.C. State was surrounded by hope and optimism, and then you wake up one day near mid-February and the Wolfpack is near last place.

More on the ACC's most disappointing team later. For now, there are contenders to discuss, and with three weeks to go no less than five teams -- North Carolina, Virginia, Florida State, Louisville and Duke -- are in the running to win the ACC's regular-season championship (which does exist, by the way).

Those five teams are all separated by one game in the loss column atop the league standings. Never before in league's 15-team era -- which, OK, only goes back to 2014 -- have so many teams been so close together near the top of the standings this late in the season.

Last year on Feb. 12, four teams were separated by one game in the loss column atop the ACC standings: UNC, Virginia, Louisville and Miami. The Tar Heels won the regular season by one game over Virginia and Miami.

Two years ago at this point nobody was within a game in the loss column of Virginia, which was 10-1 in the ACC on Feb. 12 before winning the regular season with a 16-2 league record. (Duke, which finished in second at 15-3, did all right in March and early April and won the national championship.)

Three years ago at this point, the ACC had become a two team race between Syracuse (which started 11-0 in its first season in the ACC) and Virginia (11-1). The Cavaliers were the better team in the final weeks and won the first of its consecutive regular-season ACC championships.

So yes, this year is different. We're approaching mid-February, and it's not a two-team race in the ACC, as it was in 2014, or even a four-team race, as it was a season ago. Five teams can all legitimately win this thing -- and remember that only four teams will earn the double-bye in the ACC tournament.

Let's take a closer look at those five teams. Here, in the order of where they stand now, is why they'll win the regular season championship, why they won't and their remaining schedules, which in a lot of ways could dictate these teams' direction in the final few weeks.

1. UNC (21-5, 9-3 ACC) 

Remaining schedule: at N.C. State; vs. Virginia; vs. Louisville; at Pittsburgh; at Virginia; vs. Duke

Combined ACC record of remaining opponents: 38-33

Schedule rank (among five contenders): 3

Why the Tar Heels will win the ACC: Because their best is probably better than any other team's best in the ACC, and the Tar Heels will need their best to make it through a challenging closing stretch with their second consecutive regular-season championship. Beyond that, there's a lot to like here.

UNC is the most balanced team in the ACC -- and perhaps the country -- with its ability to score on the inside and on the perimeter. When the 3-pointers are falling, the Tar Heels are all but unbeatable, assuming Kennedy Meeks and Isaiah Hicks remain engaged and productive on the inside.

Why they won't: UNC's defensive slide continued at Duke, and there's no evidence that it will be fixed any time soon. The Tar Heels' defensive woes are odd, because in November and most of December, this was among the best defensive teams in the country.

UNC hasn't been lately, though. Not even close. As junior forward Theo Pinson put it after the defeat at Duke, the Tar Heels won't be a championship team of any kind unless it starts getting stops, and those have become rarer in recent weeks.

2. Virginia (18-5, 8-3) 

Remaining schedule: at Virginia Tech (Sunday); vs. Duke; at UNC; vs. Miami; at N.C. State; vs. UNC; vs. Pitt

Combined ACC record of remaining opponents: 43-41

Schedule rank: 4

Why the Cavaliers will win the ACC: Because nobody in the league runs its system better than Virginia. This is arguably the league's best defensive team (Louisville is the only other one in the debate), and London Perrantes, while not as flashy as Dennis Smith, Jr. and not as much of a scorer as Joel Berry, is arguably the league's best, most efficient point guard.

That's a good combination: great defense and a great point guard. These Cavaliers aren't as talented as they have been in recent years, but they're still difficult to score against (third nationally in defensive efficiency, according to kenpom.com) and the closing stretch is tough but manageable.

Why they won't: Virginia isn't as talented as the other teams on this list. That might not matter a whole lot given the Cavaliers' playing style and, undoubtedly, their preference for low-possession games mitigates the talent disparity.

But still, as well as Virginia has played this season, there's no Malcolm Brogdon -- or even an Anthony Gill -- to complement Perrantes, who is the Cavaliers' only double-digit scorer. A system and scheme can only take a team so far. Does Virginia have the players to win a championship, regular season or otherwise?

3. Florida State (21-5, 9-4) 

Remaining schedule: at Pitt; vs. Boston College; at Clemson; at Duke; vs Miami

Combined ACC record of remaining opponents: 22-39

Schedule rank: 5

Why the Seminoles will win the ACC: Because they have, by a wide margin, the most favorable remaining schedule of any of the league's five contenders -- if, and it's a big if, they can win games they should on the road. Those would be the games at Pitt and at Clemson.

Win those two, and the Seminoles could reasonably finish with only one more conference loss, which perhaps would give them a share of the regular-season championship. Beyond the favorable schedule, Florida State might be the most difficult to defend team in the ACC, what with its size and skill.

Why they won't: All four of Florida State's conference losses have come on the road, and three of its final five games are on the road. The Seminoles are objectively better than at least four of their final five opponents -- and they're arguably better than Duke -- but can they get it done away from home?

4. Louisville (20-5, 8-4) 

Remaining schedule: at Syracuse; vs. Virginia Tech; at UNC; vs. Syracuse; at Wake Forest; vs. Notre Dame

Combined ACC record of remaining opponents: 44-31

Schedule rank: 2

Why the Cardinals will win the ACC: Because they have the ACC's best backcourt, with junior point guard Quentin Snider, who's back after missing six games with a hip injury, and Donovan Mitchell, who has emerged as an ACC Player of the Year candidate. And, oh yes: The Cardinals are a nasty bunch defensively.

At times Louisville has looked like it belongs in the conversation as the ACC's best team -- especially when it won three consecutive games not too long ago by at least 23 points. Like UNC, Louisville has an enviable blend of interior size and skill on the perimeter.

Why they won't: The Cardinals have already lost twice against Virginia, and they've only defeated one team (Duke) with a winning record in ACC play. Four of Louisville's final six games are against teams with winning records in the league, and so the schedule becomes more difficult than it has been.

Another problem for Louisville: This isn't a particularly good shooting team. The Cardinals are 160th nationally in effective field goal percentage, according to kenpom.com, and streaky shooting can leave Louisville more vulnerable than it should be.

5. Duke (20-5, 8-4) 

Remaining schedule: at Virginia; vs. Wake Forest; at Syracuse; at Miami; vs. Florida State; at UNC

Combined ACC record of remaining opponents: 46-28

Schedule rank: 1

Why the Blue Devils will win the ACC: Because, at last, the pieces are coming together here and are starting to form one cohesive unit. For long stretches this season, Duke didn't look so much like a team as it did a group of individuals back on the high school summer league circuit.

Add in the injuries, the nonsense (some of it self-created) surrounding Grayson Allen and Mike Krzyzewski's leave while he recovered from back surgery, and no wonder Duke floundered for so long. But all that is in the past, and Duke proved with its victory against UNC that, when at its best, it's among the ACC's best, too.

Why they won't: This could be something of a "too little, too late" scenario for Duke, which, like UNC, needed to take advantage of the softer part of their schedule. There was no shame in losing against Florida State and Louisville, but losses against Virginia Tech and N.C. State, especially, are a different story.

Now if it's to win the regular season, Duke essentially has no margin for error. That's asking a lot against the most difficult closing stretch any team will face in the ACC.

TRENDING UP 

Duke's national championship prospects. 

Grayson Allen, Luke Kennard and Jayson Tatum were all fantastic in the victory last week against UNC, and here comes Duke, indeed, back again as a contender to go far in March (and beyond).

Bonzie Colson as an ACC Player of the Year favorite. 

Colson, the Notre Dame senior forward, is coming off of two monster games: 33 points and 13 rebounds in a victory against Florida State, and 27 points and 16 rebounds in a victory against Wake Forest. In the wide-open competition for ACC Player of the Year, Colson took a big step forward.

TRENDING DOWN 

N.C. State. Again. 

The Wolfpack have to be the most disappointing team in the country. Remember the victory at Duke _ the one N.C. State hoped would be a turning point? It might turn out to be the Wolfpack's final win. A serious question: Can it get any worse for N.C. State?

"The ACC is the best conference ever" talk. 

ESPN analyst Jay Bilas said recently during the ACC Now Podcast (be sure to listen, weekly) that he doesn't buy the notion that the ACC, this season, is the best conference in college basketball history. He's right. The league is deep, and great, but it might not be as strong as it was just last season.

FINAL FOUR 

Four questions surrounding the Big Four that will be answered in the next four weeks:

1. Will UNC find its defense in time for the NCAA Tournament?

2. Has N.C. State won its final game under coach Mark Gottfried?

3. How much better, if at all, does Duke become after beating UNC at home last week?

4. Can Wake Forest position itself for its first NCAA tournament bid since 2010?