Respuesta :
C, the assassination. Thank you for letting me help you! I love helping people! :)
I believe the answer is: C. assassination of Archduke Ferdinand
Archduke Ferdinand of Austria was assasinated by a terrorist named Gavrillo Princip, which is a citizens of Serbia. This create a massive tension between the two countries which lead up to both of them seeking alliances to strengthen their millitary and eventually ended up in the world war I.