भारतीय राज्यघटना कोणत्या दिवशी स्वीकारल्या गेली ?

The correct answer is Option A (26 Nov. 1949).

Key Points:
• The Constituent Assembly of India formally adopted, enacted, and gave to themselves the Constitution on 26 November 1949.
• As explicitly stated in the Preamble: '...in our Constituent Assembly this twenty-sixth day of November, 1949, do hereby adopt, enact and give to ourselves this Constitution.'
• Hence, 26 November 1949 is the Day of Adoption of the Constitution, which is celebrated as 'Constitution Day' (Samvidhan Divas) in India.
• While certain provisions relating to citizenship, elections, provisional parliament, and temporary articles came into force immediately on 26 November 1949, the remaining major part of the Constitution came into effect on 26 January 1950 (Commencement Date / Republic Day).
• ⏳ The Constituent Assembly took 2 years, 11 months, and 18 days to frame the Constitution under the Drafting Committee chaired by Dr. B. R. Ambedkar.
• Key Takeaway: The Constitution of India was officially adopted by the Constituent Assembly on 26 November 1949.