(A) ** unrestricted submarine warfare
(B) the sinking of the Titanic
(C) imperialism in Africa
(D) creating the League of Nations
EXPLANATIONS BELOW
Concept note-1: -Germany’s resumption of submarine attacks on passenger and merchant ships in 1917 was the primary motivation behind Wilson’s decision to lead the United States into World War I.
Concept note-2: -Germany retaliated by using its submarines to destroy neutral ships that were supplying the Allies. The formidable U-boats (unterseeboots) prowled the Atlantic armed with torpedoes. They were Germany’s only weapon of advantage as Britain effectively blocked German ports to supplies.
Concept note-3: -There have been four major campaigns of unrestricted submarine warfare, one in World War I and three in World War II: The U-boat campaign of World War I, waged intermittently by Germany between 1915 and 1918 against Britain and her allies.
Concept note-4: -The American reaction to Germany’s announced intention of resuming unrestricted submarine warfare, violating the Sussex Pledge, was to declare war on Germany.