Final answer:
The President of the United States is responsible for authorizing the appointment of enlisted personnel to the U.S. Naval Academy as the Commander in Chief of the Army and Navy.
Step-by-step explanation:
The appointment of enlisted personnel to the U.S. Naval Academy is primarily authorized by the President of the United States. As the Commander in Chief of the Army and Navy, the President holds the power to oversee the appointments within the U.S. armed forces. This is specified in the Constitution, where it outlines the roles and responsibilities of the President, including being the head of the military and requiring the Senate's approval for certain appointments and treaties.