Answer:
A. Germany
Explanation:
Germany signed the treaty of Versailles at the end of world war 1 on June 28, 1919 and it went into effect on January 10, 1920.
When writing this paragraph, be sure to mention that as Britain encouraged emigration to each of the colonies, GDP in those colonies increased drastically because there was more manpower.
1- During this period of time Japan became an established liberal democracy. They also developed the modern party system where business leaders played a heavy part on politics.
2- General Yuan Shikai attempted to establish a dynasty by declaring himself the emperor of China, however after his death loads of local warlords fought for the power and it ended with economy collapse and famine.
3- Social order was threatened by local warlords therefore the politic party Kuomingtang and the communists began the northern expedition however due to a conflict of interests between the members the civil war begun.
4- Because of the national security they promise. Also, because they've got the upper hand in regards to military power
5- Because as mentioned in answer #3 The Kuomingtang united forces with the Communists against Japan as they once did with the local warlords in order to protect their country against the external threat
Hope this helps!