Which was a cause of world war 1?
A. Russia's desire to stay out of military alliances
B. The unification of separate German states into one nation
C. The invasion of Belgium by German troops
D. Austria-Hungary's imperialist ambitions to dominate the Balkans
The best option would be "B. The unification of separate German states into one nation," since this led to a strong sense of nationalism and an "us vs. them" mentality in the region.
