What action should you take if the air pressure gauge indicates low pressure?

Answer: B — Pull over and investigate

When the air pressure gauge indicates low pressure, it is crucial to pull over and investigate the situation immediately. Low air pressure can affect the braking system's performance, significantly increasing the risk of accidents. Ensuring the safety of yourself and passengers is paramount. Stopping allows you to determine the cause of the low pressure, which could stem from a leak or other issues that need to be addressed before continuing your journey. Continuing to drive slowly, adjusting tire pressure, or increasing engine RPM does not effectively address the underlying issue of low air pressure and can lead to unsafe driving conditions. These actions may temporarily mask the problem but do not resolve it, potentially putting everyone at risk. The correct response is to safely pull over and assess the situation thoroughly.