Guess? I’ve fought so many Karins on and offline. I’m about to throw my stick out. 
Became plat and now they are real pain in the a**
cr.MK is good against Karin it’s one of Bison’s poke that reach the farthest. You can play footsies a bit with this button. I also use s.HP a lot unless I’m playing a “jumpy” Karin. You can also do s.HK and Psycho Axe pre-emptively from further out than usual and try and catch Karin far reaching limbs and v-skill in her footsies.