Which one of the following is referred to in the Constitution of India

Which one of the following is referred to in the Constitution of India as the ‘Date of its Commencement’ ?

14th November, 1949
17th October, 1949
26th January, 1950
26th November, 1949
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UPSC Geoscientist – 2022
The Constitution of India is referred to have commenced on 26th January, 1950. This date is celebrated as Republic Day in India.
While certain provisions relating to citizenship, elections, provisional Parliament, etc., came into force on 26th November, 1949 (the date of adoption and enactment of the Constitution), the bulk of the Constitution and its Preamble came into effect on 26th January, 1950.
The date 26th January was specifically chosen for the commencement of the Constitution to commemorate Purna Swaraj Day, which was first celebrated on 26th January, 1930, following the Lahore Session (1929) resolution of the Indian National Congress.