(A) Militarism
(B) Alliances
(C) ** Imperialism
(D) Nationalism
EXPLANATIONS BELOW
Concept note-1: -This increase in militarism helped push the countries involved into war. The immediate cause of World War I that made the aforementioned items come into play (alliances, imperialism, militarism, nationalism) was the assassination of Archduke Franz Ferdinand of Austria-Hungary.
Concept note-2: -Difference in policies were to blame, although the immediate cause of World War one was the assassination of Austria’s Archduke Franz Ferdinand. The war started mainly because of four aspects: Militarism, Alliances, Imperialism and Nationalism.