Final answer:
The ship should fly the personal flag of the captain at half-mast as a sign of respect.
Step-by-step explanation:
When the captain of a ship dies, it is traditional for the ship to fly the flag at half-mast as a sign of respect. In the case of this question, the student is asking which pennant should be flown at half-mast. The correct pennant to fly at half-mast when the captain dies is the personal flag of the captain (also known as the CO flag or the Commodore's flag). This is a special flag that represents the rank and authority of the captain on board the ship. By flying the CO flag at half-mast, the ship is honoring the memory of the captain and showing respect for their leadership.