What is the highest military officer rank that can be achieved in the Navy according to the text?

The highest military officer rank that can be achieved in the Navy is Fleet Admiral. This rank is a five-star designation that is reserved for wartime use and has only been awarded a limited number of times in U.S. history. The title of Fleet Admiral signifies the highest level of authority and command within the Navy, surpassing roles such as Admiral (a four-star rank) and others listed in the options. While an Admiral holds significant command and responsibilities, Fleet Admiral represents the pinnacle of naval command structure, reflecting supreme leadership during major conflicts. This distinction is not typically conferred during peacetime and highlights the special stature that comes with extraordinary contributions and leadership in the naval forces.