What duty can the Coast Guard perform related to customs?

The correct response highlights the Coast Guard's authority to carry firearms and make warrantless arrests ashore. This authority stems from their dual role as both a military service and a law enforcement entity. The Coast Guard is empowered to enforce customs laws and regulations, which includes the ability to detain individuals suspected of violating these laws without the need for a prior warrant. This capability is critical in ensuring compliance with customs and immigration regulations, especially in scenarios where immediate action is necessary to prevent illegal activities such as smuggling.

In contrast, inspections of foreign ships in international waters is primarily the responsibility of the flag state, and while the Coast Guard can engage in safety inspections, they don't have the same level of customs enforcement authority in international waters. The obligation to inspect cargo is limited to specific authorized checkpoints, so inspecting cargo without proper authorization isn't within their operational scope. Tracking suspicious vessels in U.S. waters is part of their surveillance duties; however, it does not encompass the broader enforcement actions associated with customs, which includes direct arrests or interventions stemming from customs violations.