Final answer:
The Secretary of the Navy (SECNAV) is the sole approval authority for Naval decorations to members of the U.S. Public Health Service (USPHS).
Step-by-step explanation:
The sole approval authority for Naval decorations to members of the U.S. Public Health Service (USPHS) is the Secretary of the Navy (SECNAV). This person is responsible for overseeing the actions of the Navy and Marine Corps, including the distribution of awards and decorations. Although the President serves as the Commander in Chief of the Armed Forces, routine approval of decorations does not typically reach the presidential level unless it is for very high-ranking awards.