The correct answer is "that the main purpose of religion was to keep the oppressed classes of society from rebelling."
The Communist Revolution tried to stamp out the practice of religion by closing temples and expelling monks and nuns from monasteries because the communists believed that the main purpose of religion was to keep the oppressed classes of society from rebelling.
China experienced the growth of a Communist movement that challenged the ruling Nationalist government in the years after World War.
Mao Zedong was the leader of the Communists that defeated the troops of the Nationalist Party in the Chinese Civil War. So on October 1, 1949, Mao Zedong proclaimed the foundation of the People´s Republic of China. It was Mao who established Communism in China with the support of the Soviet Union. Mao was the generator of the Cultural Revolution and the Great Leao Foward.