What is the distance requirement for spacing between lights on a towing light?

The correct answer recognizes that there is no specific regulation delineating an exact distance requirement for spacing between lights on a towing light under the COLREGs. This flexibility allows mariners to position lights according to their operational needs, as long as the lights serve their purpose of ensuring visibility and safety at night or in conditions of restricted visibility.

While the other choices suggest specific measurements, the absence of a strict regulation means that spacing can vary based on the design and function of the vessel and its towing configuration. This ensures that every vessel can adapt its lighting to maximize visibility and compliance with safety standards, taking into account its unique characteristics and operational circumstances.