(A) ** Alliances
(B) Nationalism
(C) Militarism
(D) Imperialism
EXPLANATIONS BELOW
Concept note-1: -Russia was generally supportive of these plots. The successful plot to assassinate Franz Ferdinand on 28 June 1914 was part of a bigger plan. The plotters hoped that by killing Franz Ferdinand, they would provoke the Austro-Hungarian Empire to declare war on Serbia.
Concept note-2: -On July 28, 1914, one month to the day after Archduke Franz Ferdinand of Austria and his wife were killed by a Serbian nationalist in Sarajevo, Austria-Hungary declares war on Serbia, effectively beginning the First World War.
Concept note-3: -Following the Balkan Wars of 1912-1913, Serbia emerged as a larger and more assertive presence in south-east Europe. On 28 June 1914, a Bosnian-Serb terrorist shot and killed Archduke Franz Ferdinand, heir to the Austrian throne.
Concept note-4: -The Causes of World War One Austria blamed Serbia, which then looked to Russia for support. Germany declared war on Russia in support of Austria and on France because of her alliance with Russia. Britain declared war on Germany in support of Belgium and France, and on Turkey because of her alliance with Germany.