Villian has been at the table for awhile. I don't think he would make this play without at least the K.

PokerStars No-Limit Hold'em, $0.25 BB (7 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG ($26.30)
MP1 ($19.70)
MP2 ($26.55)
CO ($13.85)
Hero ($18.95)
SB ($25.35)
BB ($13.65)

Preflop: Hero is Button with 4, A.
1 fold, MP1 raises to $0.75, 2 folds, Hero calls $0.75, SB calls $0.65, 1 fold.

Flop: ($2.50) K, 3, 5 (3 players)
SB checks, MP1 bets $0.75, Hero raises to $3, SB folds, MP1 raises to $5.25, [color=#CC3333]Hero ???