Answer: b. Austria-Hungary, itself a mostly Slavic nation, supported Serbian nationalism.
Explanation:
Austria-Hungary may have had a large Slavic population but were not Slavs themselves with the Austrians being German. Austria-Hungary hated Serbian nationalism and sought to curtail the independence of the Serbian nation.
It was this reason that led to Serbian nationalists killing Archduke Franz Ferdinand of the Austria-Hungary empire, a killing which led to the first conflict in the first World War and led to the start of the most brutal war the world had seen at the time.
