The correct answer is option 2: Constituent Assembly. The Constitution of India was not framed by the Planning Commission, the President, or the Working Committee.

The Constituent Assembly of India was a body of elected representatives who were responsible for drafting and adopting the Constitution. It was formed in 1946 and consisted of members who were elected by the provincial assemblies and nominated by the princely states. It included prominent leaders like Dr. B.R. Ambedkar, Jawaharlal Nehru, and Sardar Vallabhbhai Patel.

The Constituent Assembly worked for almost three years, discussing and debating various provisions of the Constitution, and ultimately adopted it on November 26, 1949. The Constitution came into effect on January 26, 1950, marking the establishment of India as a democratic republic.