Correct answer: (3) Assassination of Archduke Franz Ferdinand
Explanation/context:
In the years prior to the outbreak of war, alliances between European nations were being made in various directions -- often by secret negotiations. Sometimes the fact that alliances were being made was announced publicly -- but the negotiations about the alliances were conducted behind closed doors. And often the terms of the alliances were kept secret, so that only the parties involved knew the full details. This business of conspiring and posturing in regard to alliances contributed to an attitude of escalating nervousness and tension as the nations of Europe maneuvered for strength over against their perceived adversaries. This was a fundamental problem that lay behind the ultimate outbreak of the Great War (as World War I was called at the time it occurred).
When Austrian Archduke Franz Ferdinand was assassinated in Sarajevo in 1914 by Serbian nationalists, the reactions by the Austrian and Serbian governments kicked into gear various alliances that had been made. Russia stood ready to protect Serbia. Germany sided with Austria over against Russia. Before long the whole affair plunged Europe into war, pulling the other nations into the conflict in support of prewar alliances they had made.
