Where is the air pressure gauge for the service tanks located?

Answer: B — On the dashboard

The air pressure gauge for the service tanks is located on the dashboard because this placement allows the driver to easily monitor the air pressure while operating the vehicle. The dashboard is designed to provide quick access to essential information and controls, making it the most practical location for a gauge that needs regular observation to ensure safe braking performance. This visibility helps drivers maintain awareness of the air supply available for brakes, which is crucial for safe operation, especially in commercial vehicles that rely heavily on air braking systems. Other locations, such as under the hood, near the compressor, or on the rearview mirror, would not provide the same level of accessibility and visibility necessary for effective monitoring during driving.