(A) 1939-1945
(B) 1860-1865
(C) ** 1914-1918
(D) 1870-1871
EXPLANATIONS BELOW
Concept note-1: -World War I or the First World War, (28 July 1914 – 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history.
Concept note-2: -World War I, also known as the Great War, began in 1914 after the assassination of Archduke Franz Ferdinand of Austria. His murder catapulted into a war across Europe that lasted until 1918.
Concept note-3: -World War I occurred between July 1914 and November 11, 1918. By the end of the war, over 17 million people would be killed including over 100, 000 American troops.