$0.05/$0.10
SB: $24.60 (246 bb)
BB: $10.15 (101.5 bb)
UTG: $41.52 (415.2 bb)
MP: $13.90 (139 bb)
Hero (CO): $17.80 (178 bb)
BTN: $10 (100 bb)

Villain unknown

Preflop: Hero is CO with Qd Ah
2 folds, Hero raises to $0.30, BTN folds, SB raises to $1, BB folds, Hero calls $0.70

AQ std defend I think

Flop: ($2.10) Th Jh 3s (2 players)
SB bets $1.60, Hero calls $1.60

Turn: ($5.30) As (2 players)
SB checks, Hero checks

xb here for pot control

River: ($5.30) 6s (2 players)
SB bets $4.60, Hero ?

When he checks turn he looks very capped to me. I think he would bet all his 2pair+, that's what makes me so hesitant on the river. He's huge bet on R looks so polarised too. What's the best play here?