Final answer:
b) when the key is first turned on and the engine is off. The correct time to verify that all the instrument lights function properly is
Step-by-step explanation:
The correct answer is option B: when the key is first turned on and the engine is off. This is the time when the vehicle's instrument panel lights, also known as the indicator lights or warning lights, should all illuminate briefly as part of a bulb check.
This self-test function is designed to confirm that the individual lights are functioning correctly before starting the car. If any of the lights do not turn on during this initial power-on sequence, it could indicate a burnt-out bulb or an issue with the vehicle's system corresponding to that light.
It is important to address any lights that do not illuminate during this check to ensure that all warning systems are operational while driving. Checking these lights while the vehicle is already in motion, or while cranking the engine, would not effectively reveal problems, as some lights are meant to only be on under those conditions.
This is when the dashboard's self-test occurs, highlighting any potential issues with the lights or vehicle systems before the vehicle is started.