(A) communism
(B) constitutionalism
(C) institutionalism
(D) ** nationalism
EXPLANATIONS BELOW
Concept note-1: -However, by 1917, the continued submarine attacks on U.S. merchant and passenger ships, and the “Zimmermann Telegram’s” implied threat of a German attack on the United States, swayed U.S. public opinion in support of a declaration of war.
Concept note-2: -In what ways did the entry of the United States into World War I contribute to the defeat of the Central Powers?-The mobilization of over 1 million U.S. troops helped French and British troops halt and turn the German spring offensive in 1918.