Correct option is C
On December 31, 1929, Jawaharlal Nehru, who was then the President of the Indian National Congress, unfurled the tricolour flag at the Lahore session. This historic event took place on the banks of the Ravi River and marked the declaration of Purna Swaraj or complete independence from British rule, to be celebrated on January 26, 1930. This moment became a precursor to India's independence struggle and is commemorated as Republic Day after India gained independence.