Step 1: Understanding the question.
The question asks when the Constitution of India was formally adopted.
Step 2: Historical context.
The Constitution of India was adopted by the Constituent Assembly on 26th November
1949. However, it came into force on 26th January 1950, which is celebrated as Republic Day.
Step 3: Analysis of the options.
• (A) 11th January 1948: Incorrect. The Constitution was not prepared on this date.
• (B) 26th November 1949: Correct. The Constitution of India was adopted on this date by the Constituent Assembly.
• (C) 26th January 1950: Incorrect. This is the date when the Constitution came into force, not when it was prepared.
• (D) 17th March 1949: Incorrect. This is not the correct date for the adoption of the Constitution.
Step 4: Conclusion.
The Constitution of India was adopted on 26th November 1949, making option (B) the correct answer.
Final Answer: 26th November 1949.