(A) April 1918
(B) ** April 1917
(C) April 1915
EXPLANATIONS BELOW
Concept note-1: -U.S. Enters World War I On April 6, 1917, the United States formally declared war against Germany and entered the conflict in Europe.
Concept note-2: -And on April 6, 1917, the United States declared war on the German Empire, joining France, Great Britain, Russia, Canada, Australia, New Zealand, South Africa and Italy.
Concept note-3: -Germany’s resumption of submarine attacks on passenger and merchant ships in 1917 became the primary motivation behind Wilson’s decision to lead the United States into World War I.
Concept note-4: -The Battle of Arras (also known as the Second Battle of Arras) was a British offensive on the Western Front during the First World War. From 9 April to 16 May 1917, British troops attacked German defences near the French city of Arras on the Western Front.