PokerStars No-Limit Hold'em, $0.50 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG ($52.75)
UTG+1 ($20.20)
MP1 ($23.45)
MP2 ($98)
MP3 ($45.25)
CO ($114.45)
Button ($8.25)
Hero ($48.75)
BB ($109.55)

Preflop: Hero is SB with 4, 4.
5 folds, CO calls $0.50, 1 fold, Hero completes, BB checks.

Flop: ($1.75) J, 4, 5 (3 players)
Hero bets $1.5, BB calls $1.50, CO folds.

Turn: ($4.75) 7 (2 players)
Hero bets $4, BB raises to $9.5, Hero ???

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Villian was 38/23 over 20 hands. This was my first orbit at the table, so I hadn't seen him in action yet.

Your move on the turn?