(A) Nationalism
(B) Imperialism
(C) ** Alliances
(D) Militarism
EXPLANATIONS BELOW
Concept note-1: -During the conflict, Germany, Austria-Hungary, Bulgaria and the Ottoman Empire (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Canada, Japan and the United States (the Allied Powers).
Concept note-2: -Allied powers, also called Allies, those countries allied in opposition to the Central Powers (Germany, Austria-Hungary, and Turkey) in World War I or to the Axis powers (Germany, Italy, and Japan) in World War II.
Concept note-3: -The Central Powers, also known as the Central Empires, was one of the two main coalitions that fought in World War I (1914–1918). It consisted of the German Empire, Austria-Hungary, the Ottoman Empire, and the Kingdom of Bulgaria and was also known as the Quadruple Alliance.
Concept note-4: -The Allied Powers were largely formed as a defense against the aggression of Germany and the Central Powers. They were also known as the Entente Powers because they began as an alliance between France, Britain, and Russia called the Triple Entente.