Who is the Constitutional and Executive Head of the Union of India?

Given below are two statements: Assertion (A): India is not a signatory to the Nuclear Non-Proliferation Treaty (NPT). Reason (R): The NPT recognizes only the five permanent members of the UN Security Council (P5) as legitimate nuclear-weapon states. Select the correct answer:

Which of the following is NOT a Fundamental Right under Part III of the Constitution of India?