PokerStars No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($52.60)
SB ($27.60)
Hero ($49.25)
UTG ($31.40)
MP ($50.70)
CO ($43.70)

Preflop: Hero is BB with 9, Q.
UTG calls $0.50, 1 fold, CO calls $0.50, Button calls $0.50, SB completes, Hero checks.

Flop: ($2.50) A, T, 5 (5 players)
SB checks, Hero ???

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Villians are unknowns in this spot.

What is your move generally here? What about on a T72 rainbow board?