Adriver complains that the brake pedal slowly moves toward the floor when the vehicle is stopped at traffic lights. pumping the pedal temporarily returns the pedal to the proper height. also, the brake fluid has been checked and is at a normal height in the reservoir. technician a says that a bad master cylinder could be the cause of the problem. fluid could be leaking internally in the cylinder. technician b says that a leaking wheel cylinder could be allowing pressure to drop. who is correct? a. a only. b. b only. c. both a and b. d. neither a nor b.