most likely to drop you

Incoming freshman
Most likely to drop for grades usually under a 3.4/ 3.5 = Pi Phi, Theta, possibly Kappa. Chi O also drops for grades but a little less picky
Most likely to drop for looks = Tri delt, Kappa, A Phi, usually zeta although recently their return rates have sucked so they most likely wont this year
Others that consider all around girls would be Chi O, maybe DG