Mack or Carson

I have a problem but it’s a good problem to have. I’m having trouble deciding who to start in my 2nd flex spot. I can have 2 RB/2 flex and it’s a standard league but RBs get a point every 5 yards. I need a win this week and here’s what I’m going with:

Kareem Hunt
Dalvin cook
Lamar Miller

I need help deciding between Marlon Mack or Chris Carson in my final flex position.