The correct option is 2 only.
Explanation
The Constituent Assembly of India was constituted in November 1946 under the scheme formulated by the Cabinet Mission Plan. It was a body tasked with drafting the Constitution for independent India.
Statement 1 is Incorrect: The Constituent Assembly was not directly elected by the people of India on the basis of adult franchise. Direct elections were considered too time-consuming and logistically difficult given the prevailing political conditions.
Statement 2 is Correct: The members of the Constituent Assembly were chosen by indirect election by the members of the Provincial Legislative Assemblies. The representatives of each community were elected by members of that community in the provincial legislative assembly, and voting was by the method of proportional representation by means of the single transferable vote.
Statement 3 is Incorrect: The Provincial Legislative Assemblies, whose members elected the Constituent Assembly, were established under the Government of India Act, 1935. The Indian Independence Act, 1947, was passed later to transfer power and partition the country; it did not establish the Provincial Legislative Assemblies that participated in the 1946 elections.
Key Takeaway: The Constituent Assembly was a partly elected (indirectly) and partly nominated body. The electoral college for the elected members consisted of the members of Provincial Legislative Assemblies established under the Government of India Act, 1935.