What does a solid yellow line on the road indicate?

Answer: B — Passing is prohibited

A solid yellow line on the road indicates that passing is prohibited for vehicles traveling in either direction. This marking serves as a clear warning to drivers that it's unsafe to overtake another vehicle due to potential visibility issues, curves, or other road conditions that could create a hazard. The purpose of this regulation is to enhance safety on the road by preventing potentially dangerous maneuvers. In contrast to other markings, such as a broken yellow line that indicates passing is allowed when it's safe, or a solid white line that relates to lane discipline, the solid yellow line explicitly instructs drivers to remain in their lanes and not attempt to pass. Understanding the significance of road markings is crucial for safe driving, as they provide important guidance on how to navigate various situations and maintain order on the road.