Explanation:
Only 5 states are considered Nuclear Weapons States (NWS) as recognized by the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as Nuclear Non-Proliferation Treaty (NET). They are – USA, Russia, France, UK, and China. So, ans is a) 1 and 2 only.
There are few other states that have nuclear weapons, like India, Pakistan and North Korea. Further, it is also believed that Israel possess nuclear weapons. However, they are not recognized as NWS under NPT. This discrimination is one of the causes why India has not yet signed the NPT.
