I think B. Provide a decent income
The alliances system meant that a local conflict could easily result into an intimidating global one. The overall cause of World War was the assassination of Archduke Franz Ferdinand. Nationalism was a great cause of World War one because of countries being greedy and not negotiating.
Your welcome I don't know if that helped. But yea.
Answer:
the german exspansion was because the german people where angry at the treaty of versilles and the apeasment made Hitler think that no one would say no
explanation: