A red X above a reversible lane indicates that the lane is closed and must not be used by drivers. It's a traffic management tool to direct the flow of vehicles and ensure safety. The correct answer to the student's question is option 1.
When driving on the road with reversible lanes, a red X means that the lane is closed and cannot be used. This is intended to control the flow of traffic and can be changed depending on the time of day or traffic conditions. Therefore, the correct answer is that a red X indicates that the lane is closed and cannot be used. It's crucial for drivers to obey these signals to ensure safety on the roads. If a lane is marked with a red X, drivers must not enter or remain in that lane, as it may be used for opposing traffic or be closed due to construction or accidents.
So, always observe reversible lane signals and switch lanes safely if you encounter a red X above your lane.