What is the primary mission of the United States Navy?

The primary mission of the United States Navy is to maintain and employ naval forces to achieve national objectives. This encompasses a broad range of responsibilities and capabilities, including power projection, strategic deterrence, maritime security, and sea control. By maintaining a strong naval presence, the Navy can respond rapidly to global crises, protect U.S. interests, and support joint operations with other branches of the military. This mission aligns with the Navy’s role in ensuring freedom of navigation, deterrence of aggression, and preparedness to operate across a spectrum of military and humanitarian situations.

The other choices, while they may represent aspects of the Navy’s activities or roles, do not capture the comprehensive scope of its primary mission. Protecting U.S. coastal waters is a part of maritime security, and land-based military operations and international diplomacy, though important, are typically conducted by other branches of the military or specific governmental entities. Thus, the correct answer reflects the overarching duty of the Navy to use its naval power strategically to fulfill the objectives set forth by national policy.