No reads on villain, getting 3-1 on river call

$0.1/$0.25 No Limit Holdem
6 players
Converted at weaktight.com

Stacks:
UTG ($26.20)
UTG 1 ($57.89)
CO ($25.00)
Hero ($21.25)
SB ($24.33)
BB ($22.08)

Pre-flop: ($0.35, 6 players) Hero is BTN
3 folds, Hero raises to $0.75, 1 fold, BB calls $0.50

Flop: ($1.60, 2 players)
BB bets $0.75, Hero raises to $3, BB calls $2.25

Turn: ($7.60, 2 players)
BB bets $2.25, Hero raises to $7, BB calls $4.75

River: ($21.60, 2 players)
BB goes all-in $11.33, Hero ???