On which holidays does the Navy observe a 21 gun salute at 1200?

The Navy observes a 21-gun salute as a display of respect and honor during significant national holidays. The correct choice highlights President's Day and Memorial Day as these holidays have specific historical and commemorative significance.

President's Day honors the birthdays of Presidents George Washington and Abraham Lincoln, recognizing their contributions to the formation and governance of the United States. Memorial Day is a solemn occasion dedicated to honoring military personnel who have died in the line of duty, making a 21-gun salute particularly fitting as a mark of respect for their sacrifice.

The other holidays listed in the answer choices do not typically receive the same recognition in terms of a 21-gun salute. While various holidays may feature different forms of military honors, the salute maintains its specific association with President's Day and Memorial Day within the Navy's ceremonial practices.