Answer:
Austria, Yugoslavia, Czechoslovakia.
Explanation:
The Empire of Austria-Hungary, following the debacle of World War I in 1918, was formerly split into 4 countries, Austria, Hungary, Czechoslovakia, and Yugoslavia, with the remaining territories being acquired mainly by Italy and Romania, as well as some other countries.
Austria-Hungary formerly dissolved in October 17, 1918.
Learn more about Austria-Hungary's role in World War I, here:
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