Something strange happened to me in the cardroom tonight and I want your honest opinion on what you would do...

My Stack size $450
CO $450

The blinds are 1-1-3, 7 handed (thanks covid). UTG+1 limps, CO raises to $6, button calls, SB (me) raises to $21, all fold to CO who calls. UTG+1 limps a lot and folds easily to pressure, same as button, CO plays a lot and will call most preflop raises.

Flop: 5♣7♠8♣

I have J♣4♥ and bet $36
CO calls

Turn: 5♠

I bet $65
CO calls

River: Q♣

At this point I have realized that I probably can't steal the pot and check in defeat...

CO bets All-in

I look at my cards for one last time and then give them the "you tried" double tap on the table in defeat ... Before I make any action (besides the gesture) CO throws his cards to the dealer, face down.

Would you: A) Call the bet and open your cards
Or... B) Muck your cards