If fog suddenly descends and visibility declines rapidly, you should...?

Answer: C — Pull off the road and wait for conditions to improve

If fog suddenly descends and visibility declines rapidly, the best course of action is to pull off the road and wait for conditions to improve. Continuing at the same speed or turning on the high-beam headlights can both be dangerous, as you may not be able to see potential obstacles in the road. Increasing your speed to exit the foggy area may also increase your risk of getting into an accident. Pulling off the road and waiting for conditions to improve is the safest option.