After the ______, Mahatma Gandhi called off the Non-Cooperation Movement.

Correct option is B

After the Chauri Chaura incident, Mahatma Gandhi called off the Non-Cooperation Movement.
The Chauri Chaura incident took place on February 5, 1922, in Chauri Chaura, a town in the Gorakhpur district of Uttar Pradesh, India.
On 5th Feb of 1922, the protest became violent when protesting people set fire a police station, burning 22 policemen alive.
The Jallianwala Bagh Massacre, also known as the Massacre of Amritsar, occurred on April 13, 1919, when British troops opened fire on a sizable crowd of unarmed Indians in an open area known as the Jallianwala Bagh in Amritsar, Punjab region (now in Punjab state), killing several hundred and injuring many more.
The Bengal partition was the partition of the Bengal province of British India in 1905.
The Round Table conferences were a series of conferences held between British and Indian leaders in the 1930–1932 to discuss the future of India.