Which organization is known for safeguarding U.S. maritime interests?

The U.S. Coast Guard plays a crucial role in safeguarding U.S. maritime interests, making it the correct answer. This organization is tasked with a variety of missions related to maritime safety, security, and environmental protection. One of its primary responsibilities includes enforcing maritime law, conducting search and rescue operations, and ensuring the safety of navigation in U.S. waters.

The Coast Guard's multifaceted approach encompasses preventing illegal fishing, drug trafficking, and other illicit activities at sea, while also responding to emergencies and mitigating environmental hazards. In addition to these responsibilities, the Coast Guard also contributes to national security by protecting ports and waterways from potential threats and coordinating with other agencies during maritime crises.

While the other organizations mentioned have important roles in national security and transportation, they do not specifically focus on maritime interests in the same comprehensive way as the Coast Guard. For instance, the Department of Transportation oversees transportation systems broadly, including highways and public transit, but does not have the same direct involvement in maritime operations.