This guy seems to play fairly straightforward against me, so this seems like a call or fold. Based on his style and the speed of his raise, I think two pair or better constitutes a good part of his range, although Q-Q is a possibility. This is probably just reducible to a math problem, but I'm too lazy to figure it out. What do you guys think?

PokerStars No-Limit Hold'em, $2 BB (6 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($203.40)
SB ($96.90)
BB ($255.30)
UTG ($427.85)
Hero ($326.45)
CO ($188)

Preflop: Hero is MP with K, J.
UTG calls $2, Hero raises to $8, 1 fold, Button calls $8, 2 folds, UTG calls $6.

Flop: ($27) 9, 3, T (3 players)
UTG checks, Hero bets $16, Button raises to $40, UTG folds, Hero ?