It's pretty simple to do the math. While all three teams are really good this year, Kentucky is closer to the 2000 game milestone. Even IF North Carolina beats Kentucky (that's a big IF) at Rupp, the Cats will not likely lose many of their remaining games this year. Probably won't lose many on their way to Indianapolis next April.
It's pretty simple. While all 3 teams are really good this year, Kentucky has the the fewest games to reach this milestone.