The correct answer is the Non-cooperation movement.
The Non-Cooperation Movement was the " first mass movement" organized under Gandhiji's leadership.
Proposal for the "Non-Cooperation Movement" was passed in the Calcutta session of Congress on 4 September 1920.
Non-cooperation Movement:
The Non-cooperation movement by Gandhiji was followed from September 1920 to February 1922.
Jallianwala Bagh Massacre in Amritsar in 1919 was one of the major reasons for the start of the Non-cooperation movement.
The Chauri Chaura incident occurred at Chauri Chaura in the Gorakhpur district (Uttar Pradesh) on 4 February 1922, when a large group of protesters, participating in the Non-cooperation movement, clashed with police, who opened fire.
As the incident turned violent Mahatma Gandhi called off the ‘Non-cooperation Movement’ on 12 February 1922, as a direct result of this incident.
Lord Edwin Montagu (1917-22) was the Secretary of state for India during the launch of the non-cooperation movement.