The correct answer is A) A vessel towing astern. According to the navigation rules, a vessel towing astern, regardless of whether it is operating in international or inland waters, would exhibit sidelights when underway and not making way. This is because the towing vessel is still considered underway, even if it is not actively propelling itself forward. The other answer choices are incorrect because: B) A vessel not under command would exhibit all-round red lights, C) A vessel engaged in dredging operations would exhibit the appropriate day shapes and lights for a vessel restricted in its ability to maneuver, and D) A vessel trawling would exhibit sidelights when making way through the water, but not necessarily when not making way.