BOTH INTERNATIONAL & INLAND In the daytime, you see a large sailing vessel on the beam. You know that she is also propelled by machinery if she shows __________.

Correct Answer: Option C — a black cone

Under COLREG Rule 25(e), any vessel proceeding under sail that is simultaneously being propelled by machinery must exhibit a black cone with its apex downward in a prominent forward location, providing mandatory daytime notice that engine power is actively contributing to the vessel's propulsion.