What does a roadway with a single solid line indicate?

Answer: B — No passing zone

A roadway marked by a single solid line indicates that the area is a no passing zone. This designation is intended to enhance safety by preventing drivers from overtaking another vehicle in areas where visibility may be limited, such as on hills or curves. The solid line serves as a clear visual warning that passing is not permitted at that location, helping to reduce the likelihood of collisions and ensure safer driving conditions. In contexts where other markings are present, such as dashed lines or specific signage, those would indicate different driving behaviors. For instance, a dashed line signifies that passing is permitted when safe to do so. However, the presence of a single solid line removes that option, reinforcing caution and compliance with traffic safety rules.