Final answer:
Mao Zedong was the leader of the communists in China from 1949 until 1976 and was the key figure behind the establishment of the People's Republic of China and the development of Maoism. Option B is correct.
Step-by-step explanation:
The leader of the communists in China from 1949 until his death in 1976 was Mao Zedong. He was a communist revolutionary who emerged as the leader of the People's Republic of China after defeating the nationalist forces led by Chiang Kai-shek. Mao Zedong developed a unique form of Marxism, known as Maoism, which emphasized the role of the peasantry in the communist revolution. Under his rule, China underwent significant transformations, including the Cultural Revolution, which aimed to enforce communist ideology.