The pump shall automatically shut off the _____ when not in operation.

The correct answer pertains to the function of the pump in a mechanical system where it must maintain efficient operation. When the pump is not in operation, it is essential that it does not continue supplying water or other fluids unnecessarily, which could lead to wastage or other operational inefficiencies. Therefore, the pump is designed to automatically shut off the supply to prevent any fluid from passing through when the pump is not actively functioning.

In mechanical systems, shutting off the supply when the pump is not in operation prevents issues such as backflow, pressure loss, and potential damage to the pump itself due to dry running. If the supply remains open, it could lead to complications in the system and increased wear and tear on the pump. The design of automatic shut-off features is critical in maintaining the longevity and efficiency of mechanical systems.