Answer:
D
Explanation:
<u>PLEASE BRAINLY THIS!!!!!!!!</u>
<u>I only need one more to up ranks</u>
That would be nationalism in the Balkans. Prior to WWI, Austria-Hungary had annexed Bosnia and Herzegovina, angering many in the Balkans especially those who wished to see a unified Yugoslavia. One such group was the Young Bosnia revolutionary organization, whose membership included Gavrilo Princip, the man who assassinated Archduke Franz Ferdinand in 1914, thus starting WWI.