Villian is 57/16. His line screamed flush draw to me. Do you call the river?

Party Poker No-Limit Hold'em, $ BB (10 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

SB ($26.23)
BB ($102.85)
UTG ($41.20)
UTG+1 ($425.22)
UTG+2 ($104.80)
MP1 ($98.37)
MP2 ($0)
MP3 ($36.75)
Hero ($103.65)
Button ($38.80)

Preflop: Hero is CO with K, A. SB posts a blind of $0.50.
UTG calls $1, UTG+1 raises to $2, 3 folds, Hero raises to $6, 4 folds, UTG+1 calls $4.

Flop: ($14.50) 5, K, 7 (3 players)
UTG+1 bets $1, Hero raises to $10, UTG+1 calls $9.

Turn: ($34.50) T (3 players)
UTG+1 bets $1, Hero raises to $20, UTG+1 calls $19.

River: ($74.50) T (3 players)
UTG+1 bets $75, Hero ???????