The rear fog light must be used in case of...
A)sudden braking.
B)night frosts.
C)dense clouds of smoke.Correct
# Rear Fog Light
The rear fog light is used specifically when there are **dense clouds of smoke, fog or heavy rain** that significantly reduce visibility. This very bright red light allows other vehicles to see you from behind in low visibility conditions, improving road safety. It must not be used under normal conditions or during sudden braking, as it would unnecessarily dazzle other drivers.