Boat A sails downwind on PortT. approaches group of StarB tack boats. Marginally crosses both Boat B and Boat C who were on StarB tack. Boat B does not protest or show flag. Boat C protests and shows flag. Boat A does 1 turn after not hearing any protest from Boat B. Boat C protests claiming that the turn was for fouling Boat B and Boat A gets DSQ.