What are the two main components of a basic air brake system?

Answer: B — Compressor and reservoir

The two main components of a basic air brake system are the compressor and the reservoir. The compressor is responsible for generating the compressed air needed to operate the braking system. It takes in atmospheric air and compresses it, which is then directed into the air reservoir. The reservoir stores the compressed air until it's needed for braking. This storage allows the brake system to function effectively, providing a reserve of air pressure that can be used to activate the brake mechanisms. Understanding the roles of these components is crucial for ensuring the safety and functionality of air brake systems in commercial vehicles. Other options mentioned, such as a master cylinder or vacuum pump, pertain to different types of braking systems, such as hydraulic brakes, and thus do not apply to air brake systems.