The answer is Lahore.

The Lahore session of the Indian National Congress was held in December 1929. At this session, the Working Committee of the Congress was authorized to launch a program of civil disobedience. The resolution passed at this session declared that India`s goal was complete independence, and that the Congress would launch a program of civil disobedience to achieve this goal.

The other Congress sessions you listed were not as significant in terms of the Indian independence movement. The Bombay session was held in 1915, and the Lucknow session was held in 1916. The Tripuri session was held in 1939, and it was notable for the election of Subhas Chandra Bose as Congress President.

However, the Lahore session was the most important of these four sessions because it was at this session that the Congress decided to launch a program of civil disobedience. This program of civil disobedience eventually led to India`s independence in 1947.