(A) the German invasion of Poland
(B) repeated violation of treaties by Japan
(C) enemy bombing of American military bases
(D) ** German unrestricted submarine warfare
EXPLANATIONS BELOW
Concept note-1: -Germany also believed that the United States had jeopardized its neutrality by acquiescing to the Allied blockade of Germany.
Concept note-2: -On December 7, 1941, following the Japanese bombing of Pearl Harbor, the United States declared war on Japan.
Concept note-3: -America Declares War on Germany On April 2, 1917, Wilson went before a special joint session of Congress and asked for a declaration of war against Germany, stating: “The world must be made safe for democracy.”
Concept note-4: -Answer and Explanation: The main result of Germany’s use of unrestricted submarine warfare during World War l was the entry of the United States into the conflict. Submarines had been attacking the ships of neutral countries, as well as, ships that carried civilian passengers.