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

UTG ($44.50)
UTG+1 ($11.90)
MP1 ($18.75)
MP2 ($35.85)
MP3 ($37)
CO ($50.50)
Button ($29.35)
Hero ($59.45)
BB ($82.60)

Preflop: Hero is SB with 7, K.
1 fold, UTG+1 calls $0.50, 2 folds, MP3 calls $0.50, 2 folds, Hero completes, BB checks.

Flop: ($2) 7, K, 5 (4 players)
Hero bets $1.5, BB calls $1.50, UTG+1 folds, MP3 calls $1.50.

Turn: ($6.50) 3 (3 players)
Hero bets $5, BB calls $5, MP3 folds.

River: ($16.50) 8 (2 players)
Hero ???

---

BB has been liberally calling raises (53/7 over 28 hands).

What's your move on the river?