The correct answer is option 1: 26 January, 1950. This is the date when the Constitution of India officially came into force.

Option 2, 26 January, 1952, is not correct as it is not the date of the Constitution coming into force, but rather the first elections being held in India after independence.

Option 3, 15 August, 1948, is also incorrect as it is the date of India`s independence from British rule, but not the day the Constitution came into force.

Option 4, 26 November, 1949, is close to the correct answer but not the exact date. This is the date when the Constitution was adopted by the Constituent Assembly of India.

Therefore, the correct answer is option 1, 26 January, 1950, the day when the Constitution of India officially came into force.