AQs UTG - 3-bet river?

[Thigh]

Thought I would ask a question here. I'm trying to get better at reading what other players have. Since villain called two bets cold PF, in the middle, what set would he have flopped?

I'm thinking possible hands he has are: JJ, TT, 44, 55, AT, QT.

The only thing I can see is T's. Maybe I'm giving villain too much credit. I guess he could have 4's or 5's, but I'm not sure I would call two bets PF in the middle with that. Like I said, I'm trying to get better at reading opponents.

As far as 3-betting the river. I would have called, even though I'm not quite sure he really did flop a set. I just think he could have QT just as easily.