What is shown in the image?

The correct answer is "D. Watch for falling rocks." This is because the image typically depicts a yellow diamond-shaped sign with a symbol of a falling rock, indicating that there is a potential hazard of rocks falling onto the road ahead. It is essential for drivers to be cautious and alert for any loose rocks that might fall onto the road while passing through that area. The other options are incorrect as they do not match the warning sign shown in the image.