400nl: AA top set scary river OOP

[DiceMan14]

Villain is 21/16/1.2 and has been straightforward so far. On river he has $268 left and I cover.

Full Tilt No-Limit Hold'em, $4 BB (6 handed) Full Tilt Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

CO ($412.30)
Button ($442.45)
SB ($744)
BB ($1132.60)
UTG ($533)
Hero ($575.70)

Preflop: Hero is MP with A[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $14</font>, <font color="#666666">1 fold</font>, Button calls $14, SB calls $12, BB calls $10.

Flop: ($56) A[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/spade.gif[/img], K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, BB checks, <font color="#CC3333">Hero bets $40</font>, Button calls $40, SB folds, BB calls $40.

Turn: ($176) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, <font color="#CC3333">Hero bets $120</font>, Button calls $120, BB folds.

River: ($416) 3[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero ??