Final answer:
In extremely dense fog, you should turn on your headlights and fog lights, drive at a slower speed, and increase the following distance between your vehicle and the one in front of you. The correct answer is 'All of the above'.
Step-by-step explanation:
In extremely dense fog, safety is the primary concern. When visibility is significantly reduced, it is advisable to:
- Turn on your headlights and fog lights. This action makes your vehicle visible to other road users.
- Drive at a slower speed. Reduced visibility means that hazards on the road are harder to see, so decreasing your speed allows you more time to react.
- Increase the following distance between your vehicle and the one in front of you. In dense fog, stopping distances can be longer, and increasing the gap gives you a safety buffer.
Therefore, the correct answer to what you should do in extremely dense fog is 4) All of the above.