How can a driver identify a blown air line?

Answer: B — By inspecting for visible damage or listening for escaping air

A driver can identify a blown air line effectively by inspecting for visible damage or listening for escaping air. When an air line is compromised, it can result in a significant loss of air pressure, which is critical for the operation of air brakes. Visual inspection allows the driver to spot any noticeable damage to the air lines, such as cracks, frays, or separation from fittings. Additionally, the sound of escaping air serves as an immediate indicator of a potential issue. This method is directly related to the core functionality of air brake systems, as these systems rely on a constant supply of compressed air to operate safely and efficiently. Recognizing the signs of a blown air line is crucial for maintaining the braking system's integrity and ensuring vehicle safety on the road. Other options do not directly pertain to diagnosing air line issues specifically; hence, they would not provide the clear and immediate identification needed in such a situation.