A single dashed yellow line usually marks the centerline of a two-way roadway where

Answer: B — vehicle may pass if safe

On a two-way roadway, a dashed yellow line usually marks the centerline to indicate that passing is allowed. Passing on a roadway with a solid yellow line is not allowed, as it indicates that there is limited visibility and passing could be dangerous. Option A is incorrect because passing is allowed on a two-way roadway with a dashed yellow line. Option C is incorrect because stopping is generally not required or indicated by a dashed yellow line. Option D is incorrect because pedestrians are generally not allowed to cross in the middle of a two-way roadway.