Final answer:
The assassination of Archduke Ferdinand is credited for starting WWI.
Step-by-step explanation:
The event that is credited for starting World War I is the assassination of Archduke Ferdinand. On June 28, 1914, Archduke Franz Ferdinand of Austria-Hungary was assassinated by a Serbian nationalist in Sarajevo. This event sparked a chain reaction of diplomatic tensions and military mobilizations, ultimately leading to the outbreak of war.
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