200nl - river bet sizing

[converted_hand][hand_history]Yatahay Network - $2 NL FAST (6 max) - Holdem - 6 players
Hand converted by Holdem Manager 3

BTN: $659.21 (329.6 bb)
SB: $200.00 (100 bb)
BB: $319.74 (159.9 bb)
Hero (UTG): $261.78 (130.9 bb)
MP: $259.34 (129.7 bb)
CO: $266.59 (133.3 bb)

SB posts $1.00, BB posts $2.00

Pre Flop: (pot: $3.00) Hero has 5♦ 4♦
Hero raises to $5.00, 2 folds, BTN raises to $17.00, 2 folds, Hero calls $12.00

Flop: ($37.00, 2 players) 7♦ 9♦ K♣
Hero checks, BTN bets $12.21, Hero calls $12.21

Turn: ($61.42, 2 players) Q♠
Hero checks, BTN checks

River: ($61.42, 2 players) J♦
Hero ??

Whats our bet sizing here?