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

Button ($83.10)
SB ($95.50)
BB ($101.10)
UTG ($59.25)
UTG+1 ($115.05)
Hero ($100)
MP2 ($71.80)
MP3 ($29.45)
CO ($34.50)

Preflop: Hero is MP1 with J, J.
2 folds, Hero raises to $4, MP2 calls $4, 1 fold, CO calls $4, 2 folds, BB calls $3.

Flop: ($16.50) 3, 5, 2 (4 players)
BB checks, Hero bets $12, MP2 raises to $67.8, CO folds, BB folds, Hero ???

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Against a complete unknown, what's your default line here?