What must you do when driving in fog?

Answer: B — Use low beams and reduce speed

When driving in fog, using low beams and reducing speed is essential for safety. Low beams emit a light that is directed toward the road without reflecting off the fog, rain, or snow, which helps improve visibility without causing glare. High beams, on the other hand, can create a blinding effect as the light reflects off water droplets in the fog, making it difficult to see ahead. Reducing speed is also critical because fog can significantly reduce visibility, making it harder to see obstacles, other vehicles, and road signs. Driving at a normal speed in these conditions could lead to dangerous situations as you may not have enough time to react to unforeseen circumstances. Turning on parking lights is not advisable either, as they do not provide sufficient illumination for navigating low-visibility conditions. Therefore, using low beams and reducing speed effectively increases your safety and the safety of others while driving in fog.