The best answer is:
B. Mao implemented the Cultural Revolution to regain control of the Communist Party after the failures of the Great Leap Forward.
The Cultural Revolution, initiated by Mao Zedong in 1966, aimed to reinforce communist ideology and purge perceived counter-revolutionary elements from the Communist Party and Chinese society, particularly following the setbacks of the Great Leap Forward (1958-1962), which had led to economic disruption and widespread famine. Mao sought to reassert his authority and re-establish his vision for China through this movement.