(A) ** build up of large militaries and intense nationalism in Europe
(B) Germany’s submarine warfare against America
(C) Spanish mistreatment of Cubans and Filipinos
(D) Formation of a weak League of Nations
EXPLANATIONS BELOW
Concept note-1: -The assassination of Austrian Archduke Franz Ferdinand (June 28, 1914) was the main catalyst for the start of the Great War (World War I).
Concept note-2: -Nationalism led to this situation because it was responsible for pushing countries to expand their influence in Europe. This caused tensions between the major powers of Europe. For example, there was an intense arms race and naval race between several European nations in the buildup to World War I.
Concept note-3: -Nationalism was a prominent force in early 20th century Europe and a significant cause of World War I. Nationalism is an intense form of patriotism or loyalty to one’s country.