Three Bet or just Call

Live 4/8
I am UTG, raise with A [img]/images/graemlins/diamond.gif[/img]T [img]/images/graemlins/diamond.gif[/img], next to act called two cold, everyone else folded to the blinds who both called, 4 people saw the flop:
A [img]/images/graemlins/spade.gif[/img]K [img]/images/graemlins/club.gif[/img]6 [img]/images/graemlins/diamond.gif[/img]
Both blinds check to me, I bet, Fold, small blind (who was pretty loose, especially from the blinds) called, big blind folded. Heads up to the turn:
T [img]/images/graemlins/heart.gif[/img]
Check, I Bet, Call. River
8 [img]/images/graemlins/club.gif[/img]
Check, I bet, the other guy raises. My read on this guy wasn't the best, but i did know he was pretty loose passive. I couldn't rule out him having a 97, but i thought it was very unlikely so there is no way i'm folding to two bets. I figure i have three lines; call, three bet and call four bets, or three bets and fold to a four bet. What is my best line?