If a low air pressure warning occurs for only one system in a dual air brake system, what is the correct action?

Answer: B — Stop and safely park until fixed

A low air pressure warning for one system in a dual air brake system signifies a potential failure in that braking system, which could jeopardize vehicle safety. The correct action in this scenario is to stop and safely park the vehicle until the issue is fixed. This is crucial because the dual air brake system is designed for redundancy; if one system experiences a problem, the other may not be enough to ensure safe stopping. Continuing to drive could lead to a complete brake failure, posing a significant risk to the driver and others on the road. Addressing the issue immediately by pulling over allows for a thorough check of the braking systems and prevents the possibility of a serious accident caused by inadequate braking power. Ignoring or downplaying the warning can lead to catastrophic consequences, which is why immediate action is vital.