6-handed game. Button is 20/13/3ish and attempts to steal the blinds ~30% of the time. SB is also standard TAG and they've been reraising preflop a few times but didn't show anything down or get it past a c-bet or something. Effective stacks 100BB.

Button opens 3½ bb, SB reraises to 12bb, BB folds, Button calls.

Flop low rags (25bb in pot). SB bets 20bb, Button pushes. SB needs to call 68bb to win 200bb.

What is the optimal calling range of SB?