Which component of the air brake system is responsible for activating the brake shoes?

Answer: B — Brake chamber

The brake chamber is a crucial component of the air brake system because it converts the air pressure that comes from the compressor into mechanical force. When the driver presses the brake pedal, air is sent from the reservoir to the brake chamber. Inside the brake chamber, this air pressure moves a diaphragm, which in turn pushes the brake shoes against the brake drums. This action generates the friction required to slow down or stop the vehicle. Understanding the function of the brake chamber is vital, as it essentially acts as the interface that translates the driver's intention (via the brake pedal) into tangible braking action. This makes the brake chamber a fundamental part of the air brake system that ensures the vehicle can stop safely and effectively.