What is the primary function of headlights during the nighttime driving?

Answer: B — To illuminate the road ahead

The primary function of headlights during nighttime driving is to illuminate the road ahead. This is essential for safe navigation in low-light conditions, as it allows drivers to see obstacles, road markings, and other vehicles clearly. Proper illumination enables drivers to gauge distances, recognize potential hazards, and make informed decisions while driving. While signaling other drivers and deterring animals might play minor roles in some driving situations, the core purpose of headlights fundamentally revolves around visibility and ensuring a clear path during the hours of darkness. The aesthetic enhancement of a vehicle is not a practical function of headlights, and deterring animals, while a potential side effect, is not their main purpose.