(A) Nationalism
(B) Imperialism
(C) ** Alliances
(D) Militarism
EXPLANATIONS BELOW
Concept note-1: -The Allies, or the Entente powers, were an international military coalition of countries led by the United Kingdom, France, Russia, Italy, Japan, and the United States against the Central Powers of Germany, Austria-Hungary, the Ottoman Empire, Bulgaria during the First World War (1914–1918).
Concept note-2: -By 1910 most of the major states of Europe belonged to one or the other of these great opposing alliances: the Central Powers, whose principal members were Germany and Austria-Hungary, and the Allies, composed of France, Russia, and Great Britain.
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: -In World War II, the three great Allied powers-Great Britain, the United States, and the Soviet Union-formed a Grand Alliance that was the key to victory.