Correct answer: A. To turn complete independence into a public pledge
Explanation: The direct answer is Option A: the observance of 26 January turned the demand for complete independence into a public pledge. The Indian National Congress declared Poorna Swaraj as its goal at the Lahore session in December 1929. It decided that 26 January 1930 would be observed as Independence Day. On that day, people publicly affirmed that India should achieve complete independence, not merely limited self-government under British rule. Option A is therefore correct. Option B, increasing British army recruitment, was a colonial objective and was not the purpose of observing the day. Option C, welcoming the Simon Commission, is wrong because the Simon Commission had been opposed in India; it was associated with the slogan against its arrival, not with the Poorna Swaraj observance. Option D, separating princely states, was not the aim of the national pledge. The date later became Republic Day in 1950, linking the Constitution with the earlier freedom pledge. Memory cue: 1930 means Poorna Swaraj Day; 1950 means the Constitution came into force and Republic Day began.