What years did Archibald Henderson serve as the Commandant of the Marine Corps?

Archibald Henderson served as the Commandant of the Marine Corps from 1820 to 1859. His tenure is particularly significant because he was the fifth Commandant and held the position for nearly 39 years, which is one of the longest serving periods in the history of the Corps. During his leadership, Henderson greatly influenced the development of the Marine Corps, establishing it as a formidable fighting force and enhancing its role in naval and military operations. He was instrumental in improving training and discipline within the ranks, and his legacy includes a focus on professionalism and preparedness that still influences the Corps today. This extensive duration and impactful leadership during a formative period in U.S. military history directly correlate with the correct identification of his years of service as Commandant, reinforcing option B as the accurate choice.