Reflectors on trailers must be mounted less than __ inches, or more than __ inches above ground.

Reflectors on trailers are required to be mounted in a specific vertical range relative to the ground to ensure visibility and safety during operation, particularly at night or in low-light conditions. The correct answer indicates that reflectors must be positioned less than 24 inches or more than 60 inches above the ground.

This height range is important because positioning reflectors within these guidelines maximizes their effectiveness. Reflectors mounted below 24 inches can be too low to be seen effectively by drivers, especially those in larger vehicles, while those mounted above 60 inches ensure that they are prominent and easily visible to other road users.

The other options do not align with the established standards, suggesting either too low or inappropriate heights for the effective visibility of the reflectors. Therefore, the range indicated is crucial for maintaining safety on the roads, ensuring that trailers are identifiable in various driving conditions.