This diamond-shaped sign indicates that...

Answer: C — A farm equipment vehicle is passing on the road

Diamond-shaped signs warn you of hazards or changes ahead. The sign showing a tractor alerts you that farm equipment may be using or crossing the road, so you should slow down, stay alert, and be prepared to stop if a tractor enters or is on the road. This isn’t indicating a yield situation or a school or pedestrian crossing, which are shown with different symbols or shapes. The tractor symbol specifically means you’ll likely encounter slow-moving farm vehicles, so give them extra space and proceed cautiously.