When are drivers required to use low beam headlights:
Answer: B — Within 150m of the approach of another vehicle
Drivers are required to use low beam headlights when within 150m of the approach of another vehicle for safety purposes, especially at nighttime or during adverse weather conditions. This prevents the blinding of other drivers and allows for better visibility. Option A is too broad and does not specify a distance. Option C is too far and could potentially reduce visibility for the driver. Option D is incorrect because using low beam headlights is actually a law in many states for certain situations.