Fold? IMO, people could have limped/made this play with TPTK, 2 pair, straight, or some sort of OESD.

PokerStars No-Limit Hold'em, $0.10 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver Cards)

UTG ($12.65)
UTG+1 ($6.05)
MP1 ($5.05)
MP2 ($13.85)
MP3 ($8.95)
CO ($1.75)
Button ($18.50)
SB ($10)
Hero ($12)

Preflop: Hero is BB with , .
1 fold, UTG+1 calls $0.10, 1 fold, MP2 calls $0.10, 2 folds, Button calls $0.10, SB completes, Hero checks.

Flop: ($0.50) , , (5 players)
SB bets $0.4, Hero calls $0.40, UTG+1 raises to $5.95, MP2 calls $5.95, Button folds, SB folds, [color=#CC3333]Hero ?