During brake system failure, what does the emergency brake system utilize?

Answer: C — Parts of the service brake and parking brake

During brake system failure, the emergency brake relies on a combination of both systems. It uses the same wheel brake components (the parts involved in the service brakes) and the parking brake mechanism that provides a spring-applied, air-released means to apply those brakes when the normal air pressure is lost. This setup ensures you still have braking capability even if the primary service brake system isn’t functioning. The ABS system isn’t part of this emergency stopping method, so it isn’t the means by which the emergency brake stops the vehicle.