It would be all of these. During world war 2 it is the United States that supplied almost everything in the allied war effort. Also the United States take longer route and also a hard campaign to combat the German U-boat for supremacy and stable supply route for the allied forces.
We can say that all the options were a challenge from the USA in the Second World War. While at the beginning the US remained neutral, with the United Kingdom's entry into the war, the US started a way of helping by sending food and weapons, but later entering the war had to lead the front and deal with all the inconveniences mentioned. , added to its territorial distance of the place in which the battles were fought.
