$200 NL 6 max....no read

I raise to $7 with [Qd]. Button calls.

Pot $17. Flop [5c][9h]. I bet $14 and he calls.
Pot $45 Turn . he has $75 left. I bet $35. He calls.
Pot $115. River . What do you do here when he has $40 left? He either has a weak ace or just hit his flush. If he donkish enough to chase his flush with these bad odds, hes bad enough to call his last $40 with A2.

a) Put him all in
b) Check / call
c) check / fold

I guess I just think its pretty obvious he has the flush. I did push and he did have the flush with K6s. Gotta love Bodog.

Im sure it was the right play but it seems I keep running into this scenario where they have like 1/4 pot left on the river when the flush hits and I know they have it, but shoving the turn wouldve been an overbet. Sometimes I shove the turn anyway, but that cant be the highest EV play.

Ice, I am curious what your action would have been had he raised enough to commit himself on the flop??