What should drivers do if they notice the low-air warning light illuminated?

Answer: B — Immediately check the air pressure

If the low-air warning light is illuminated, it indicates a potentially serious issue with the air brake system that requires immediate attention. The correct action for drivers to take is to check the air pressure without delay. This is crucial because low air pressure can impair the effectiveness of the air brakes, increasing the risk of brake failure. Taking swift action to verify the air pressure helps ensure that the vehicle remains safe to operate. If the air pressure is indeed low, drivers can then take appropriate measures, such as finding a safe location to stop and addressing the air pressure issue, whether that means adding air, seeking maintenance, or replacing faulty components. Ignoring the warning light, increasing speed, or turning off the engine could exacerbate the situation, leading to loss of vehicle control or a dangerous driving scenario.