The United States belongs to the following international associations:
B. United Nations
E. North Atlantic Treaty Organization (NATO)
The United States was a founding member of the United Nations and is a key member of NATO. It is not a member of the Warsaw Pact (A), the League of Nations (C), or the British Commonwealth (D). The Warsaw Pact was a military alliance of Soviet-aligned countries during the Cold War, the League of Nations was an earlier international organization that the U.S. did not join, and while the U.S. has historical ties with the British Commonwealth, it is not a member.