In what circumstances does the vice president assume the office of president?

Correct option is B

The correct answer is (b) During casual vacancy due to death, resignation, removal, or otherwise
Explanation:
• As per Article 65 of the Indian Constitution, the Vice-President acts as President when a vacancy occurs.
• This may be due to the death, resignation, removal, or otherwise of the President.
• The Vice-President discharges the duties of the President until a new one is elected.
• In the interim, all powers and privileges of the President are vested in the Vice-President.
• If the President is temporarily unavailable (illness, travel), the Chief Justice of India may be appointed to discharge duties.
Information Booster:
• The Vice-President is also the ex-officio Chairman of the Rajya Sabha.
• The acting term cannot exceed six months; fresh election must be held.
Additional Knowledge:
Only when Parliament declares it (Option a)
• Incorrect; the Constitution automatically empowers the Vice-President without needing Parliament’s approval.
When the president is on a foreign visit only (Option c)
• Wrong; temporary arrangements are handled differently (often by Chief Justice).
During elections (Option d)
• No such provision exists; the acting President role only arises due to a vacancy.