The members of the Constituent Assembly put their signatures on the final handwritten copies of the Constitution of India on:

The members of the Constituent Assembly signed the final handwritten copies of the Constitution of India, in English and in Hindi, on 24 January 1950, at the last meeting of the Assembly.

The signing:

• About 284 members signed the copies of the Constitution.
• The President of the Assembly signed first.
• The signatures were put on the handwritten copies prepared by the calligraphers.
• It was raining lightly in Delhi that day, which some members regarded as a good omen.

Other business on that day:

• On the same day, the Assembly also completed some other formal business, such as the adoption of the National Anthem and the National Song, and the election of the first President of India.
• The members sang "Jana Gana Mana" at the end of the session.
• After the signing, the Constituent Assembly ceased to exist as a constitution-making body; it continued as the Provisional Parliament of India until the first general elections (1951-52).

The signed copies:

• The signed copies are among the most treasured documents of the nation.
• They are now kept in special helium-filled cases in the Library of Parliament, New Delhi, to protect them from decay.
• The pages were decorated by artists of Santiniketan, under the guidance of Nandalal Bose.
• The English copy was signed by the members in English, and many also signed the Hindi copy, some in their own scripts.

The signatures include those of the leaders of the national movement, such as Jawaharlal Nehru, Vallabhbhai Patel, Maulana Azad and B. R. Ambedkar.

Why not the other options?

• ✗15 August 1949, 2 October 1949 and 1 April 1950 are not the date of the signing.