The correct answer is **26 November 1949** (Option 2). **Comprehensive Derivation:** The correct answer is 26 November 1949. Explanation & Key Takeaways: Constituent Assembly: • It was constituted in 1946. • The first meeting was held on December 9, 1946. • Muslim league did not participate in the first meeting. • After elections were held- Dr Rajendra Prasad and HC Mukherjee were elected as the President and Vice-President of the Assembly respectively. • Sir BN Rau was appointed as the constitutional advisor of the assembly • Constituent assembly held 11 sessions over two years, 11 months and 18 days. • The last session of the constituent assembly was held on January 24, 1950. • The final draft of the constitution was introduced in the assembly in 1948. • After subsequent readings, the constituent assembly adopted, enacted and gave to themselves the constitution on November 26, 1949. • Some provisions of the constitution came into force on the above-mentioned date. • However, most provisions came into force on January 26th, 1950. • The constitution refers to this date as the ‘date of its commencement’. This day is celebrated as ‘Republic day’ every year. **Option Elimination:** • **Option 1 (26 January 1950)**: Incorrect distractor. • **Option 2 (26 November 1949)**: Correct Answer; accurate according to canonical reference. • **Option 3 (26 January 1949)**: Incorrect distractor. • **Option 4 (15 August 1947)**: Incorrect distractor. **Exam Trap:** Be careful of misleading distractors and subtle terminology differences. Verify core properties before selecting your answer. **Memory Booster:** Core mnemonic rule: 26 November 1949 corresponds to Option (2).