The correct answer is option 3 - Lahore Congress, 1929. In the Lahore session of the Indian National Congress held in 1929, the tricolour flag was unfurled for the first time. The flag, also known as the "Tiranga," had three horizontal bands of saffron, white, and green, with a spinning wheel (charkha) in the center. The Lahore Congress session played a significant role in the Indian independence movement as it adopted the resolution of "Purna Swaraj" or complete independence from British rule. The flag became an iconic symbol of India`s struggle for freedom and was officially adopted as the national flag of India on 15th August 1947, when India gained independence.