Bet the flop. Call a raise and call down a non-scary board, but consider releasing to a 3-bet.

Checking top pair because "someone always bets" is really awful unless you're going to do something constructive with that line such as a c/r. As played you lack the necessary information to make a good decision here. You haven't defined your hand. You could be against two FDs or a flush draw and an OESD or something really awful here like A8. As played I fold, very unhappily.