In the given question, a statement of Assertion is followed by a statement of Reason. Mark the correct answer.

Assertion: The Non-Cooperation Movement was called off in February 1922.
Reason: A police station in Chauri Chaura was burned and several constables perished in the conflagration.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

In February 1922, a group of peasants attacked and torched a police station in the hamlet of Chauri Chaura, in the United Provinces (now, Uttar Pradesh and Uttaranchal). Several constables perished in the conflagration. This act of violence prompted Gandhiji to call off the movement altogether. “No provocation,” he insisted, “can possibly justify (the) brutal murder of men who had been rendered defenceless and who had virtually thrown themselves on the mercy of the mob". Due to the violent nature of the movement it was called off by Gandhiji.