Good flop not good enough?

[citizenkn]

$5 SNG at Poker Room, blinds 25-50. I have a big chip lead (4500 or so, 2nd stack is about 3000) I'm dealt Jh-Ah on the button. MP (stack of 1500 or so) raises to 125, LP calls, I call, SB calls, four to the flop.

Flop comes 4h-9h-Jc. I couldn't ask for a better flop---TPTK and the nut flush draw. Checked to initial raiser, who bets half his stack. Up to this point he had been very quiet, rarely raising, and almost never betting significantly into a pot. I call, everyone else folds. Next card is a rag, and he bets the rest of his stack. I put him on a big pair (QQ-KK-AA) and fold.

At what point did I screw this up?

a. Shouldn't have called the initial raise to begin with
b. should have folded to his bet on the flop
c. should have raised him all in on the flop
d. should have called his all in on the turn