Final answer:
The host country's national anthem is traditionally played at sunset when a ship is visiting a foreign port, as a sign of respect and adherence to maritime customs. The correct option is A.
Step-by-step explanation:
The correct time to play the host country's national anthem when your ship is visiting a foreign port is at sunset. This practice is in line with maritime tradition and diplomatic courtesy, signifying respect for the sovereignty and traditions of the host nation.
The lowering of flags and the playing of anthems typically take place at this time, as indicated by phrases such as “be duly lower'd at sunset” found in poetic excerpts, which allude to shipboard ceremonial practices aligned with the setting of the sun.
Hence, Option A is correct.