Which agency is responsible for Customs and border protection?

The correct answer is CBP, which stands for Customs and Border Protection. This agency is part of the U.S. Department of Homeland Security and is responsible for safeguarding the nation's borders, enforcing customs laws, and regulating the flow of goods in and out of the country. CBP plays a crucial role in national security by preventing illegal entry, countering smuggling operations, and facilitating lawful trade and travel.

The other options, while they may look similar, do not represent the official agency that oversees customs and border protection activities. They are not abbreviations recognized in the context of U.S. border control or customs enforcement, which further emphasizes the importance of the correct designation—CBP—as it directly reflects the agency's name and function.