When should you use your headlights while driving?

Answer: D — All of the above

You should use your headlights while driving in various situations, including in fog, during the day, and at night. Using headlights in fog enhances visibility for both the driver and other vehicles on the road. Even during the day, headlights can increase the visibility of your vehicle, making it easier for other drivers to spot you on the road. And of course, using headlights at night is necessary for safe driving due to the lack of natural light. So, all of the options listed (A, B, C) require the use of headlights while driving, making option D the correct answer.