A towing vessel pushing a barge ahead in a composite unit must show the lights of which type of vessel?

A towing vessel that is pushing a barge ahead in a composite unit must display the lights of a power-driven vessel that is not towing. This is because, when the towing vessel is pushing a barge, the barge cannot be considered as an independent vessel since it is part of the composite unit. The regulations regarding navigation lights specify that vessels engaged in pushing or towing must exhibit lights indicating that they are power-driven, but not specifically for a towing configuration.

The configuration of the composite unit allows it to be treated as a single vessel in terms of lighting requirements. When a vessel is making way with a barge being pushed in this manner, the lights shown correspond to the characteristics of a power-driven vessel. This distinction is important to ensure safe navigation and clear communication of the vessel's actions and position on the water.

For instance, the other choices would indicate different types of lighting configurations that are not applicable in this scenario. A sailing vessel would require different lights, and a vessel engaged in fishing would also have a distinct set of lights according to its activity. Similarly, a vessel under sail has its specific lighting requirements that do not pertain to vessels pushing or towing. Thus, option B accurately reflects the correct lighting configuration necessary for a towing vessel