The Soviet Union helped the Chinese communist by supporting Mao Zedong. Option B is correct.
Mao Zedong was a Chinese communist revolutionary who became the founding father of the People's Republic of China.
The Soviet Union or officially the Union of Soviet Socialist Republics (USSR),[ was a socialist state in Eurasia that existed from 1922 to 1991.
The relationship between China and the Soviet Union was know as Sino-Soviet relations.