The correct option is C The forced cultivation of indigo and other cash crops in place of food crops.
Gandhiji's first great experiment with satyagraha was accomplished in 1917 in Champaran, Bihar. The indigo cultivators of Champaran were greatly exploited by European planters. They were bound by law to grow indigo on 3/20th of their land and sell it to the British planters at prices fixed by them. They invited Gandhiji to take up their cause. He offered satyagraha as a result of which an inquiry was conducted into the conditions of the peasants.