nl50 KK faces flop decision

[PokerFun007]

PokerStars No-Limit Hold'em, $0.50 BB (9 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Button ($65.30)
SB ($47.45)
BB ($15.15)
UTG ($95.20)
UTG+1 ($46.60)
MP1 ($66.85)
Hero ($48)
MP3 ($48.90)
CO ($23.95)

Preflop: Hero is MP2 with K[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/diamond.gif[/img].
UTG calls $0.50, <font color="#666666">1 fold</font>, MP1 calls $0.50, <font color="#CC3333">Hero raises to $3</font>, MP3 calls $3, <font color="#666666">3 folds</font>, BB calls $2.50, UTG calls $2.50, MP1 calls $2.50.

Flop: ($15.25) 9[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
BB checks, UTG checks, MP1 checks, <font color="#CC3333">Hero bets $12.5</font>, <font color="#CC3333">MP3 raises to $45.9</font>, BB folds, UTG folds, MP1 folds, Hero ???