facing donk + overcall on River, TPGK, easy?

no reads. Party 2/4

Hero is CO with A[img]/images/graemlins/club.gif[/img] Q[img]/images/graemlins/diamond.gif[/img]

Preflop:
6 folds, Hero Raises in CO, Button Folds, SB calls, BB calls

Flop (6 SB): 6[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/diamond.gif[/img] 2[img]/images/graemlins/club.gif[/img]
SB checks, BB bets, Hero Raises, SB 3-bets, BB calls, Hero caps, SB calls, BB calls.

Turn (9 BB): 7[img]/images/graemlins/club.gif[/img]
SB checks, BB checks, Hero bets, SB calls, BB calls

River (12 BB): K[img]/images/graemlins/heart.gif[/img]
SB bets, BB calls, Hero ?