PokerStars No-Limit Hold'em, $1.00 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP2 ($79.50)
MP3 ($24)
CO ($57)
Button ($29.15)
SB ($41.80)
BB ($144.50)
UTG ($105)
UTG+1 ($138.20)
Hero ($100)

Preflop: Hero is MP1 with K, A.
2 folds, Hero raises to $3.75, 4 folds, SB calls $3.25, 1 fold.

Flop: ($8.50) Q, T, 2 (2 players)
SB bets $4, Hero ???

---

SB is an unknown player, no HUD stats yet.

What's your move here?