(A) The U.S. had sold the Allies many supplies and wanted to make sure they won the war.
(B) ** A note from the Germans known as the Zimmerman telegram which asked Mexico to attack the U.S.
(C) The U.S. never entered the war due to the neutrality agreement.
(D) The signing of the Treaty of Versailles.
EXPLANATIONS BELOW
Concept note-1: -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-2: -Germany promised to help Mexico take back land the United States had taken from Mexico in the Mexican–American War. These places were Texas, New Mexico, and Arizona. Germany wanted Mexico to enter the war so America would be too busy to help the enemies of Germany.
Concept note-3: -In January 1917, British cryptographers deciphered a telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, Heinrich von Eckhardt, offering United States territory to Mexico in return for joining the German cause.