The united states was called the arsenal of democracy because it was the country where all weapons were kept. it provided supplies for both the axis and allied powers. it provided supplies for the entire allied war effort. it was the country where all aircraft were housed.

Option C,  it provided supplies for the entire Allied war effort, is the right answer.

During the time of Second World War Franklin D. Roosevelt, the President of the United States in a  used the slogan the  "Arsenal of Democracy". Roosevelt declared to help the  United Kingdom to fight against Nazi Germany by providing them armed supplies, while itself staying outside the actual fighting. President Roosevelt promised the Allies in Europe to provide it with arm and support and to some extent, arm and support to the Chinese Republic, in total war against Imperial Japan and Nazi Germany. Therefore, this term "The great arsenal of democracy" is specially referred to the  U.S industry as the primary supplier of arms supply for the Allied war effort

it provided supplies for the entire Allied war effort. is your best answer

The US provided most of the weapons for the Allied powers in wars from WWI and onward, as well as create enough for their armies. Because of the amount of arms and military equipment created, as well as the size of the US military forces, the US is the "Arsenal" of Democracy.

hope this helps

first paragraph (and busy all the night ,with a silence deep and white )

it maybe, we dont know. however lucky the lipercon seams guilty