Correct Answer: (b) 26 November, 1949
Solution:The Preamble of the Constitution states, "we the People of India enact, adopt and give to ourselves this Constitution on 26 November, 1949". This date is considered as the date of adoption, completion and passing of the Constitution. On the same day the provisions relating to Citizenship, Interim Parliament and Temporary, Transitional and special provisions came into effect. The rest of the provisions came into effect on 26 January, 1950. Thus 26 January, 1950 is considered as the enforcement date of the whole Constitution.