Answer: D. Commercial vessel
Explanation: Commercial vessels are required to set yellow lights whether to tow or push a barge. They can also place more yellow lights on the stern. Also, yellow lights are placed on the bow and there can be a great distance between the lights, even from hundreds of yards, that is, there can be unlit space. It is important that the lights be at the beginning and at the end of the composition, i.e the stern and bow of the commercial vessel and the towed / pushed barge, as a whole, therefore the whole composition.
