What components are typically included in a modern air brake system?

Answer: B — Anti-lock braking system (ABS), electronic control unit, brake valves, and air reservoirs

A modern air brake system is designed for efficiency, safety, and control of heavy vehicles. It typically includes an anti-lock braking system (ABS), an electronic control unit, brake valves, and air reservoirs. The anti-lock braking system is crucial as it helps maintain traction by preventing wheel lock-up during hard braking, thus enhancing vehicle control and reducing stopping distances. The electronic control unit serves as the brain of the system, coordinating operations and making real-time adjustments to enhance brake performance and efficiency. Brake valves are essential for managing airflow and pressure throughout the braking system, allowing for precise control of the brakes. Air reservoirs store compressed air used to apply the brakes, ensuring there is always enough pressure available when needed. Other components mentioned in the choices—like carburetors, steering columns, and clutches—are related to different systems in a vehicle. Carburetors and fuel injectors pertain to fuel delivery in internal combustion engines, the steering column involves the steering mechanism, and clutches are part of the transmission system, necessary for shifting gears in vehicles with manual transmission. These components do not directly relate to the operation of air brakes and are therefore not included in a modern air brake system.