In the absence of the president of India, if vice-President is not available, who of the following can act as the President?

The answer is A) Chief Justice of India. The order of succession is set out in the Constitution and the Vice-President and President (Discharge of Functions) Act, 1969. Under Article 65, the Vice-President acts as President when the office falls vacant or the President is absent. If both the President and the Vice-President are unavailable, the 1969 Act makes the Chief Justice of India the acting President. If the CJI is also unavailable, the senior-most available judge of the Supreme Court takes over.

Why the others are wrong:

• B) Prime Minister: The PM heads the government and is not in the presidential line of succession. Making the PM acting President would also blur the separation between the head of state and the head of government.
• C) Speaker of the Lok Sabha: The Speaker presides over the Lok Sabha and is not in the succession. The Speaker is a common confusion with the Chairman of Rajya Sabha, who is the Vice-President.
• D) Attorney General of India: The AG is the government's chief legal adviser under Article 76. The office has no role in presidential succession.

This sits within the Polity syllabus on the executive and presidential succession. In Mains, it helps in discussing the constitutional safeguards that keep the office of head of state continuous. Note that the 1969 Act is a statute, not a Constitution article, so it is worth remembering by name.

Trap: Candidates pick the Speaker because the Speaker is a senior constitutional functionary. Succession runs through the judiciary, not the legislature.