Explanation:

The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is an international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy, and to further the goal of achieving nuclear disarmament and general and complete disarmament.Four states—India, Israel, Pakistan, and South Sudan—have never signed the treaty. India and Pakistan have publicly disclosed their nuclear weapon programs, and Israel has a long-standing policy of deliberate ambiguity with regards to its nuclear program