Which event lit a “powder keg” in Europe and led to the start of World War I?

The assassination of Archduke Franz Ferdinand by Serbian nationalist Gavrilo Princip in 1914 triggered a chain of events that led to World War I. Austria-Hungary blamed Serbia and declared war, and alliances drew other countries into the conflict. The correct choice is “Archduke Franz Ferdinand was assassinated by a Serbian nationalist.”

AI-written and checked against the verified answer.