When is it inappropriate to use your car's high beam headlights?

Answer: B — When there are other vehicles nearby

Using high beam headlights when there are other vehicles nearby is inappropriate due to the potential for glare to distract or blind drivers of oncoming or adjacent vehicles. High beams are designed to provide extended visibility in dark or unlit conditions, but their brightness can be overwhelming for other road users, particularly those in vehicles that are close. The purpose of using low beam headlights in the presence of nearby vehicles is to ensure safety on the road, enhancing visibility without compromising the ability of other drivers to see clearly. This rule applies universally, regardless of the specific driving conditions, as protecting the vision of all motorists is crucial for safe driving practices.