Concept:The Champaran Satyagraha (1917) was Mahatma Gandhi's first major active involvement in India's freedom struggle, based on non-violent resistance against oppressive British planters.
Explanation:In 1917, farmers in Champaran, Bihar, were forced to grow indigo under the Tinkathia system, which exploited them heavily.
Mahatma Gandhi led this movement to address their grievances.
He used the principle of Satyagraha (non-violent resistance) and successfully negotiated with the British authorities to end the oppressive system.
This event marked Gandhi's entry into Indian mass movements.
Answer:Option D – Mahatma Gandhi.