[DoomSlice]

This is a tough spot!

The truth is that BB can have a pretty wide range of hands here, since he is closing the action preflop and getting a good price to do so, so you can't automatically put him on a set.

Several hands that might make this bet that you beat are: 65, A5, A4, A3, 66

Several hands that have you beat are: A2,67, 55, 44, 33 45s, 34s

So it's time to narrow that hand range down a bit. The BB will have an excellent chance to checkraise and trap MP2 in if he slowplays the straight, so those two combinations are slightly less probable.

Sets are a possibility, but once again I think most players like to check-raise here with those.

So that leaves the slightly more vulnerable two pair hands that would lead out like that, along with the pair+draw hands.

You've got a decent chance of catching up with two pair (25%) but you're not ahead THAT much of the pair+draw hands or OESD (66). With that in mind, I like to peel one off here and then put him all in on the turn as long as a scare card doesn't hit. If one does hit, I have no problem with folding, and if MP2 or SB happen to come along for the ride, I also have no problem folding to further aggression.

Edit: Also include in the hand range mid PPs like 88-JJ, all of which make a call here even more attractive.