(A) The United States followed a policy of appeasement in regards to Germany.
(B) The United States followed a policy of isolationism at the start of the war.
(C) The United States refused to ever join the League of Nations.
(D) ** The United States provided economic and military aid to the Allies.
EXPLANATIONS BELOW
Concept note-1: -"Arsenal of democracy” refers to the collective efforts of American industry in supporting the Allies, which efforts tended to be concentrated in the established industrial centers of the U.S., such as Philadelphia, Detroit, Cleveland, Buffalo, Rochester, Chicago, New York, and Pittsburgh, among other cities.
Concept note-2: -By the time the Japanese surrendered in 1945, the United States had fulfilled President Roosevelt’s admonition to become the great arsenal of democracy.
Concept note-3: -Roosevelt built a powerful wartime coalition with Britain and the Soviet Union, and led the nation to victory against Nazi Germany. His wartime efforts prepared the path for his successor, Harry Truman, to win the war against Japan four months after his death.