What should a driver do if the air pressure drops too low?

Answer: C — Pull over and stop safely

When air pressure drops too low in an air brake system, the most appropriate action for a driver is to pull over and stop safely. This is crucial because inadequate air pressure can compromise the effectiveness of the brakes, leading to potentially dangerous driving conditions. The air brake system relies on adequate air pressure to function properly; if the pressure falls below a specific threshold, the brakes may not engage when needed or could fail entirely. Stopping safely allows the driver to assess the situation without putting themselves or others at risk. It also gives them the opportunity to troubleshoot the problem, potentially preventing further issues on the road. Continuing to drive, engaging the emergency brake, or increasing acceleration do not effectively address the serious safety concern presented by low air pressure.