The correct answer identifies the appropriate positioning of shutoff valves on A/C system service equipment hoses for safety and efficiency. Positioning the shutoff valves 12 inches from the vehicle end ensures that they are easily accessible for operation and maintenance while minimizing the risk of any refrigerant leaks or exposure to the technician.
This distance allows technicians to quickly respond to situations that may require the valves to be shut off, without having to reach excessively far into potentially hazardous areas. Additionally, it strikes a balance between accessibility and safety, ensuring that any adjustments made can be done without putting the technician or equipment at undue risk.
The other distances provided could either make the valves too difficult to reach in an emergency or place them in a position that may inadvertently interfere with the vehicle’s operation or components, which could lead to safety hazards. Hence, the 12-inch placement is preferable in accordance with industry best practices.