The warlord era gave a massive impact on the young people who got frustrated that led them to think towards ideas such as communism and nationalism that started the Chinese Civil War.
The Chinese Civil war was the military struggle that occurred for the control of the labor wages of China. This war was a result of the warlord era due to which the Chinese Civil war was started.
The Warlord era was the era of the Republic of China during the time when the control of China was given or divided among former military cliques. This led to the frustrations in the young people of China.
The frustration of the young blood led to the ideas of communism and nationalism in China.
Therefore, option D is correct.
To know more about the Chinese Civil War, refer to the link:
https://brainly.com/question/1544985