Which event is the clearest immediate trigger for World War I?

• A. The signing of the Treaty of Versailles.
• B. The assassination of Archduke Franz Ferdinand.
• C. The Crimean War.
• D. The Franco-Prussian War.

Answer: (B)

The direct spark driving World War I was the assassination of Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne, in Sarajevo in 1914. This killing set off a rapid chain of events: Austria-Hungary issued a harsh ultimatum to Serbia, and when Serbia’s response failed to meet all demands, Austria-Hungary declared war. Because Europe was tightly wound with alliances and militaristic plans, the conflict pulled in Russia, Germany, France, and eventually Britain, leading to widespread mobilizations and a continental war in just a matter of weeks.

The other events are important for understanding the broader background, but they aren’t the immediate trigger. The Crimean War and the Franco-Prussian War occurred well before World War I and helped shape 19th-century European power dynamics, while the Treaty of Versailles ended World War I, not started it.