Easy Laydown?

[parappa]

First hand. Everyone has 800 chips. Hero has BB at 10/15.

4 callers to hero, who has 8 [img]/images/graemlins/club.gif[/img]6 [img]/images/graemlins/club.gif[/img]. Hero checks.

(Pot: 60) Flop: J [img]/images/graemlins/spade.gif[/img] 6 [img]/images/graemlins/diamond.gif[/img] A [img]/images/graemlins/spade.gif[/img].

Everyone checks.

Turn: 6 [img]/images/graemlins/heart.gif[/img]

Hero bets 60. SB calls. Everyone else folds.

(Pot 180) River: 9 [img]/images/graemlins/spade.gif[/img].

SB checks. Hero thinks for a minute and bets 180. SB raises all-in.

a) Is the obvious right play to check behind on the river?
b) Can you call when check-raised?