Why Was the United States Called the "Arsenal of Democracy

Why was the United States called the "Arsenal of Democracy"?

A) It produced 300,000 airplanes, 2.6 million machine guns, 6 million tons of bombs, and numerous other war materials.
B) It symbolized how democratic nations should fight a war
C) It manufactured 1,000 ships, 500,000 rifles, and 10,000 airplanes during the war.
D) It provided all the war materials that the allies needed.
E) It supplied the allies with all necessary natural resources.