BOTH INTERNATIONAL & INLAND Two vessels are meeting in a narrow channel as shown in illustration D037RR below. Vessel "A" is a sailing vessel. Vessel "B" is a power-driven vessel which can safely navigate only within the channel. Vessel "B" sounds the danger signal. Vessel "A" shall take what action?

Correct Answer: Option C — not impede the passage of vessel "B"

Rule 9(b) mandates that a sailing vessel or a vessel less than 20 meters shall not impede the passage of a vessel that can safely navigate only within a narrow channel. Even if the sailing vessel is normally stand-on, it must yield to the constrained vessel in this scenario.