The Soviet Union help the Chinese communists by supporting Mao Zedong.
Who was Mao Zedong?
Mao Zedong also called Chairman Mao, Mao was a Chinese communist radical who was the creation father of the People's Republic of China, Mao ruled as the chairman of the Chinese Communist Party from the establishment of the PRC(People's Republic of China) in 1949 to his death in 1976.
The main competitor to the Nationalist's claim to power that could do anything about it was the Communists under Mao.
Mao Zedong, who was a Chinese communist, takes support from the Soviet Union.
As Mao Zedong thought that the employment rights of the Chinese, the South Manchuria Railway, the Port Arthur, Eastern Railway, and Dalian were part of Chinese state sovereignty,
Mao asked the Soviet Union to return these interests to China, and this was a crucial part of the Sino-Soviet Treaty of Friendship.
Therefore, option [B] is correct, where the Soviet Union help the Chinese communists.
Learn more about Chinese communists, refer:
https://brainly.com/question/1283463