Reflectors must be mounted at a height of:

The requirement for mounting reflectors at a height of no less than 15 inches and no more than 60 inches is based on safety regulations that ensure reflectors are visible to other drivers in various conditions. This specific height range allows for adequate visibility while also considering factors such as vehicle size and road conditions.

Placement within this range ensures that reflectors are positioned effectively for nighttime visibility, reducing the risk of accidents. If reflectors are mounted too low, they may not be seen by approaching vehicles, particularly those that are larger or at different elevations. Conversely, if they are set too high, they can still be out of the line of sight for many drivers, especially in lower-profile vehicles.

The other options do not align with these standards, either by being too restrictive or too permissive in terms of height, which could compromise safety. Therefore, the specification of 15 inches to 60 inches provides a balance that promotes optimal safety and visibility on the road.