What function does a push-to-test pilot light serve?

The correct answer emphasizes the purpose of a push-to-test pilot light in a motor control setup. A push-to-test pilot light is designed primarily to check the functionality of the indicator bulb itself. When the test button is pressed, the circuit momentarily energizes the pilot light to confirm that it is operational. This means that a technician can quickly verify whether the light is working properly without needing to troubleshoot the entire circuit system.

In contrast, the other options, while relevant to the function of lights and controls in general, do not directly align with the primary function of a push-to-test pilot light. Controlling circuit operation pertains to factors like relays or switches but isn't specific to the testing function of pilot lights. Indicating operational status is a general feature of many indicators but does not capture the testing aspect that the push-to-test functionality provides. Emergency lighting typically serves a safety function during power outages or emergencies, which is unrelated to the specific testing capability of the pilot light.