PokerStars No-Limit Hold'em, $1.00 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

SB ($99)
BB ($92.90)
UTG ($32.45)
UTG+1 ($32)
MP1 ($100)
Hero ($98.50)
CO ($98.50)
Button ($107.50)

Preflop: Hero is MP2 with A, K.
UTG calls $1, 2 folds, Hero raises to $4.5, 1 fold, Button calls $4.50, SB calls $4, 1 fold, UTG folds.

Flop: ($15.50) 5, T, 7 (3 players)
SB checks, Hero bets $10, Button folds, SB raises to $20, Hero ???

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Villian is a solid regular, we've played lots of hands together. He is 24/6.6/3.42 over 1400 hands.

What's your play here?