Which of the following can be used to investigate the reason the assassination of Archduke Franz Ferdinand sparked World War I?

Responses

the collapse of the alliance system
the collapse of the alliance system

the role that East African soldiers played in the war
the role that East African soldiers played in the war

knowledge of the Schlieffen Plan
knowledge of the Schlieffen Plan

the nationality of Archduke Franz Ferdinand’s assassin
the nationality of Archduke Franz Ferdinand’s assassin

Investigating the collapse of the alliance system, knowledge of the Schlieffen Plan, and the nationality of Archduke Franz Ferdinand's assassin would all be relevant in understanding the reasons why his assassination sparked World War I. The role that East African soldiers played in the war, however, would not directly relate to the specific catalyst of the assassination of Archduke Franz Ferdinand.