Which one of the following was not part of NATO?
(1) France
(2) Yugoslavia
(3) Britain
(4) Italy

2

NATO, or the North Atlantic Treaty Organization, is a military alliance that was established in 1949 with the signing of the North Atlantic Treaty. Its original membership included various Western European nations, the United States, and Canada. The purpose of NATO was to provide collective defense against the threat of expansion by the Soviet Union and its allies.
Yugoslavia, at the time under the leadership of Josip Broz Tito, pursued a socialist model of governance but was not aligned with the Soviet Union's form of communism after the Tito-Stalin split in 1948. This split led Yugoslavia to take an independent, non-aligned position during the Cold War. Although Yugoslavia had a socialist government, it was not a member of the Warsaw Pact (the military alliance of the Soviet bloc), nor was it a member of NATO.
In contrast, France, Britain, and Italy were among the founding members of NATO.