Who was the Vice-President of the executive council in the interim government formed by Congress in 1946?

Jawaharlal Nehru

The correct answer is Option 3 - Jawaharlal Nehru

On 2 September 1946 Congress forms Interim Government with Nehru as the President (of the executive council).

Timeline of important events in 1946:

16 May 1946: Cabinet Mission announces its constitutional scheme.
16 June 1946: Muslim League accepts Cabinet Mission’s constitutional scheme.
16 June 1946: Cabinet Mission presents a scheme for the formation of an Interim Government at the Centre.
16 August 1946: Muslim League announces Direct Action Day or The Great Calcutta Killings.
2 September 1946: Congress forms Interim Government with Nehru as the Vice-President.
13 October 1946: The Muslim League decides to join the Interim Government.
3-6 December 1946: British Prime Minister, Attlee, meets some Indian leaders; talks fail.
9 December 1946: Constituent Assembly begins its sessions.