Explanation:

• Russia and the USA together possess over 90 per cent of the global nuclear weapons and both China and Pakistan have larger nuclear arsenals than India.
• The U.S. and Russia have reduced their nuclear arsenals under the 2010 New Strategic Arms Reduction Treaty (New START) – a bilateral agreement, but it is set to lapse in February 2021.
• The Nuclear Non-Proliferation Treaty (NPT) recognizes five states as nuclear-weapon states: United States, Russia, the United Kingdom, France, and China (also the five permanent members of the United Nations Security Council). Hence only statements 1,2 &3 are correct.