Pingali Venkayya, an Indian freedom fighter, is best remembered for his pivotal role in the conception of which national symbol?

Explanation

Pingali Venkayya presented a flag design to Gandhi in 1921. The saffron, white and green design with a spinning wheel was adopted in 1931. In 1947, the Constituent Assembly adopted the national flag with the Ashoka Chakra replacing the spinning wheel.