Final answer:
Option C). Spring brakes are emergency/parking brakes used in air brake systems of vehicles. They engage automatically in case of a loss of air pressure to keep the vehicle stationary.
Step-by-step explanation:
Vehicle emergency and parking brakes are operated by springs. They are frequently found in air brake systems, especially in buses and trucks and other heavy-duty vehicles. In the event that the system loses air pressure, spring brakes are meant to activate automatically, serving as a failsafe to keep the car in a stationary position.
A diaphragm-type spring brake is one kind of spring brake that is frequently utilized in air brake systems. Its components include a diaphragm and a set of springs that are compressed when air pressure is applied. The diaphragm is forced to move by the springs if the air pressure falls below a predetermined point, applying the brake and stopping the car.