UTG bets 12bb after turn check-through

Multi-way River | 4-way: BTN | 100bb effective | Difficulty: Standard

Players in hand: UTG, MP, Hero (BTN), BB

Hero hand

J♥J♠

Board

9♣5♦2♠Q♥K♦

Action so far:
River K♦ on 9♣5♦2♠Q♥K♦, pot 18bb
UTG bets 12bb after turn check-through

Pot: 18bb   To call: 12bb

Villain range: UTG delayed river bet on K river: KK, KQ, Kx slowplays, AA

Your move: