When refueling the vehicle it is mandatory to...
A)turn off the lights and roll up the windows.
B)stop the engine and turn on the emergency signal.
C)turn off the lights and electrical systems, such as the radio.Correct
# Explanation: Refueling
When refueling it is mandatory to **turn off the engine and deactivate all electrical systems** (lights, radio, etc.) to avoid sparks that could cause a fire. Fuel is highly flammable, so any source of electrical ignition represents a serious danger. This is a fundamental safety measure at any gas station.