PokerStars No-Limit Hold'em, $0.50 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($114.45)
SB ($30.75)
BB ($50)
UTG ($65.25)
UTG+1 ($37.55)
MP1 ($56.70)
MP2 ($53.25)
MP3 ($69.65)
Hero ($50)

Preflop: Hero is CO with Q, 6. Hero posts a blind of $0.50.
UTG calls $0.50, 1 fold, MP1 calls $0.50, 2 folds, Hero (poster) checks, 2 folds, BB checks.

Flop: ($2.25) 6, 4, 3 (4 players)
BB checks, UTG bets $0.5, MP1 calls $0.50, Hero ???

---

I didn't have any hands on either UTG or MP1.

What's your move on the flop, and what's your plan on later streets?