The correct answer is B. The Nuclear Non-Proliferation Treaty of 1968 was an example of an international treaty with the goal of limiting the spread of nuclear weapons and promoting the peaceful use of nuclear energy.
The Nuclear Non-Proliferation Treaty (NPT) is a treaty open for signature on July 1, 1968, in effect since March 5, 1970, which restricts the possession of nuclear weapons and it is therefore part of the efforts of the international community to prevent the proliferation of weapons of mass destruction. It is integrated by the vast majority of sovereign States (190). Only five States were allowed possession of nuclear weapons: the United States (signatory in 1968), the United Kingdom (1968), France (1992), the Soviet Union (1968, replaced by Russia), and the People's Republic of China (1992). The special status of these five "Nuclear Armed States" was defined as the only ones that had detonated a nuclear test until 1967. They are the five permanent members of the United Nations Security Council.