Question: Why does the Tri-Border Area present a threat to the United States? A. Thousands of extremists live there and can pose as travelers from nearby countries friendly with the United States. B. It consists of Brazil, Paraguay, and Argentina, countries that are considered enemies of the United States. C. It consists of Iraq, Iran, and Saudi Arabia, countries that have a history of terrorism. D. Surveillance shows that there is a nuclear arsenal hidden in this area.