A. The sinking of the Lusitania
B. The assassination of Archduke Franz Ferdinand
C. The invasion of Poland
D. The bombing of Pearl Harbor
Answer: The assassination of Archduke Franz Ferdinand
What event triggered the start of World War I?
Additional Information: The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered a chain of events that led to the outbreak of World War I.
Subjects: World History, General Knowledge