4th hand at table

PokerStars No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($51.20)
SB ($49.50)
BB ($50)
UTG ($77.65)
MP ($76.25)
CO ($85.75)

Preflop: Hero is Button with A, K.
UTG raises to $2, 2 folds, Hero raises to $6, 2 folds, UTG raises to $10, Hero calls $4.

Flop: ($20.75) 8, K, 3 (2 players)
UTG bets $12, Hero ???

Hero has $41 behind, UTG has him covered