The correct answer is Sachchidananda Sinha. Explanation & Key Takeaways: • Dr Sachchidananda Sinha was the first temporary chairman of the constituent assembly. • The Constituent Assembly met for the first time in New Delhi on 9 December 1946 in the Constitution Hall which is now known as the Central Hall of Parliament House. • He was an Indian lawyer and journalist. • He has also served as a member of the Imperial legislative council and the first Indian to serve as a First finance member of the government of Bihar. • M.N Roy put the idea of the constituent assembly in 1934. • Later it became an official demand of the Indian National Congress in 1935. • C. Rajagopalachari supported this demand and it was accepted by the British in August 1940. Related Concepts: • The Constituent Assembly took almost three years (two years, eleven months, and seventeen days to be precise) to complete its historic task of drafting the Constitution for Independent India. • During this period, it held eleven sessions covering a total of 165 days. Of these, 114 days were spent on the consideration of the Draft Constitution. • As to its composition, members were chosen by indirect election by the members of the Provincial Legislative Assemblies, according to the scheme recommended by the Cabinet Mission. • The arrangement was: • 292 members were elected through the Provincial Legislative Assemblies; • 93 members represented the Indian Princely States; and • 4 members represented the Chief Commissioners Provinces. • The total membership of the Assembly thus was to be 389. • However, as a result of the partition under the Mountbatten Plan of 3 June 1947, a separate Constituent Assembly was set up for Pakistan, and representatives of some Provinces ceased to be members of the Assembly. • As a result, the membership of the Assembly was reduced to 299.