What is the primary mission of the United States Coast Guard?

The primary mission of the United States Coast Guard is to protect the public, the environment, and U.S. economic interests in the nation's ports and waterways. This encompasses a broad range of responsibilities, including search and rescue operations, law enforcement, environmental protection, and maintaining navigational aids. The Coast Guard plays a vital role in ensuring the safety of maritime commerce and safeguarding the marine environment against pollution and other hazards.

While enforcing international maritime law and managing natural resources are important functions of the Coast Guard, they fall under the broader mandate to protect the interests of the United States and its citizens within maritime contexts. Scientific research in oceanography, though valuable, is not a core mission of the Coast Guard. Thus, the first choice captures the comprehensive nature of the Coast Guard's primary responsibilities and reflects its multifaceted role in maritime safety and security.