Final answer:
Archibald Henderson was known as the Grand Old Man of the Marine Corps, serving as the 5th Commandant from 1820-1859. None of the provided options are correct.
Step-by-step explanation:
The Grand Old Man of the Marine Corps referred to is Archibald Henderson. He was not only the 5th Commandant of the Marine Corps but also served the longest term in that position to date, which stretched from 1820-1859, a total of 39 years.
None of the options provided, including General George Washington, Brigadier General Daniel Morgan, Major Benedict Arnold, or Major General Benjamin Lincoln, are correct. Archibald Henderson is known for his significant contributions to the Marines, and he played a pivotal role in expanding the Corps' duties and responsibilities.
He is a celebrated figure in Marine Corps history for his leadership and the nickname "Grand Old Man" signifies his longstanding impact on the branch.