No motor vehicle shall be used that has an obstructed view to the rear unless:

The correct answer emphasizes the importance of safety measures designed to assist drivers in navigating safely in reverse when their view to the rear is obstructed. A reverse signal alarm that is audible above the surrounding noise level alerts both the driver and others in the vicinity that the vehicle is moving. This auditory warning significantly enhances safety by making pedestrians and other personnel aware of the vehicle's motion and intentions.

While having adequate rear view mirrors is a common solution for obstructed views, the specific provision regarding the audible reverse signal emphasizes a proactive safety measure that compensates for the lack of visual cues. The other options do not adequately address the primary concern of ensuring the safety of the driver and those nearby when a vehicle cannot provide a clear view of what is behind it.