Close Primary Before Super Tuesday

[Arizona Iced Tea]

What situation do you think will give a close primary race before Super Tuesday?
Here's mine:

Iowa-41 delegates
1)Buttigeig 31.71% 13 delegates
2)Warren 26.83% 11 delegates
3)Biden 24.39% 10 delegates
4)Sanders 17.07% 7 delegates

New Hampshire-24 delegates
1)Sanders 33.33% 8 delegates
2)Warren 29.17% 7 delegates
3)Biden 25.00% 6 delegates
4)Buttigieg 12.50% 3 delegates

South Carolina-54 delegates
1)Biden 53.70% 29 delegates
2)Warren 18.52% 10 delegates
3)Sanders 11.11% 6 delegates
4)Harris 7.41% 4 delegates
5)Buttigieg 5.56% 3 delegates
6)Booker 3.70% 2 delegates

Nevada-36 delegates
1)Warren 33.33% 12 delegates
2)Biden 27.78% 10 delegates
3)Sanders 25.00% 9 delegates
4)Buttigieg 8.33% 3 delegates
5)Harris 2.78% 1 delegate
5)Yang 2.78% 1 delegate

Total delegates-155
1)Biden 55
2)Warren 40
3)Sanders 30
4)Buttigieg 22
5)Harris 5
6)Booker 2
7)Yang 1

TLDR:Each of the top four win one state. Biden wins over 50% in SC which gives him a headstart and 15 delegate lead over Warren before Super Tuesday.