A sign indicating that the right lane ends is meant to warn drivers:

Answer: A — That the right lane ends and traffic should merge left.

The sign indicating that the right lane ends is specifically designed to alert drivers that they need to merge into the left lane due to the lane they are currently in coming to an end. This type of sign is crucial for highway safety, as it allows drivers to prepare for the change in traffic patterns, thereby reducing the risk of collisions caused by abrupt lane changes. It ensures that drivers are aware of the need to adjust their position on the roadway well ahead of the point where the lane actually ends, promoting smoother traffic flow and enhancing overall road safety. The other options pertain to different traffic scenarios that are not relevant to this specific sign. The sign does not indicate road curvature, intersections, or construction work—it solely focuses on the necessity for merging due to the termination of a lane.