PokerStars No-Limit Hold'em, $2 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

UTG+1 ($274.70)
MP1 ($208.55)
MP2 ($56.10)
CO ($67)
Button ($381.55)
SB ($396.60)
Hero ($206.75)
UTG ($203.40)

Preflop: Hero is BB with K, A.
4 folds, CO raises to $6, 2 folds, Hero ???

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Usually against a full stack I will re-raise 3.5-4x the raise in this situation, as long as the player is not too nitty.

However, against this unknown 33BB stack, re-raising puts me in a awkward situation on the flop.

What's your move here?