What is the primary purpose of using low-beam headlights in fog?

Answer: B — To prevent glare in fog

Using low-beam headlights in fog is primarily intended to prevent glare. In foggy conditions, the light emitted from high-beam headlights can reflect off the fog, rain, or snow and create a blinding effect for the driver, as well as for oncoming vehicles. Low-beam headlights are designed to project light downwards and closer to the ground, which reduces the amount of light that is reflected back by the fog. This aids visibility without creating excessive glare, allowing the driver to see the road better and navigate safely through reduced visibility conditions. Options related to improving battery efficiency, increasing speed, and enhancing aesthetic appeal do not directly address the primary function of headlights in foggy situations. The focus during poor visibility conditions is on safety, making the use of low-beam headlights a practical choice to aid in safe driving.