How will we know that the brake pads are worn?

A)When pressing the brake pedal we will observe that the pads do not make contact with the brake disc.
B)We will perceive squeaking or abnormal noises when pressing the brake pedal.Correct
C)Brake pads never wear out. We must only periodically check the brake fluid.
Wear of the brake pads eventually causes friction between the metal of the brake disc and the base of the pads, so we will be able to hear squeaking.