What is the appropriate time to fly the flag at the stern flagstaff on a ship in port?

The flag is traditionally flown from the stern flagstaff of a ship in port from 0800 until sunset. This practice aligns with naval customs and traditions regarding the display of the national ensign. The rationale behind this time frame is to ensure that the flag is displayed during daylight hours when it can be seen clearly and in accordance with both naval regulations and standard maritime etiquette.

Flying the flag from 0800 ensures that it is displayed for a significant portion of the day, reflecting the ceremonial importance of the ensign and its representation of the nation's sovereignty. The specified end time of sunset allows for different time zones and variations in daylight throughout the seasons, ensuring that the flag is only flown in suitable lighting conditions.

The other options either extend the time beyond what is customary for military protocol or do not conform to expected practices of flag display, which is primarily focused on proper timing and visibility. The choice of 0800 to sunset respects both tradition and practicality.