The correct answers are B) CPC and D) KMT
The Chinese Civil War was fought between CPC and KMT - KMT were the nationalists and CPC was the Communist Party of China - it happened from 1927 to 1936.
After the fall of the Qing Dynasty, many warlords dominated a series of regions in China. The KMT leader wanted to end this domination and because of that, they started the Northern Expedition. To help with the Expedition, China sought help with the Soviet Union which decided to support the KMT and the CPC.
During the Northern Expedition, the KMT and CPC split because of that the Civil War started, all of this happened before the Second Sino-Japanese War that resulted in the invasion and occupation of Manchuria.