(A) Money, Assassination, Imperialism, Neutrality
(B) ** Militarism, Alliances, Imperialism, Nationalism
(C) Militarism, Alliances, Imperialism, Neutrality
(D) Money, Assassination, Imperialism, Nationalism
EXPLANATIONS BELOW
Concept note-1: -The war started mainly because of four aspects: Militarism, Alliances, Imperialism and Nationalism. This is because big armies become potential threats to other countries, other countries started forcing alliances in order to secure land.
Concept note-2: -One alliance included Germany, Austria-Hungary and Italy, called the Triple Alliance. Opposing them was the Triple Entente of France, Russia and England. These complex tensions finally exploded into war.