How did the assassination of Archduke Franz Ferdinand lead to ​ World War I ​ ? War broke out when Serbia refused to agree to a list of Austrian demands after the assassination.

Germany ended diplomatic relations with Austria after the assassination, resulting in the outbreak of war.

Russian troops invaded Serbia after the assassination, seeking revenge for the death of the czar’s cousin.

Troops protecting the archduke retaliated by attacking Serbian military positions after the assassination.