It was a trigger that showed that there were two competing powers in Europe: Russia and Austria-Hungary (and their allies).
Franz Ferdinand was killed by a Serbian separatist and the Austrians wanted him to be punished. On the other hand, Russia supported Serbia is saying that Austrian demands ( to be allowed to search for the culprit inside Serbia) were too much.
This lead to a direct conflict between the two powers (Austria and Russia) and further lead to the war.
Social discord, political instability and lack of compromise, economic collapse.
Option C. Germany invades Soviet Union; Allies invade Normandy; Potsdam Conference
Germany - September 17, 1939
Normandy - June 6, 1944
Potsdam - July 17-Aug.2, 1945
