Answer:
D
Step-by-step explanation:
At first the us attempted to be a neutral power but after an attack to us submarines by the germans, they were unable to mantain this position of neutrality meaning it could not be (A). Britain was actually the U.s. major trading partner during the course if the war and by no means tried to cut off U.s. supplies or aid meaning it could not be (B). And during the war millions of Americans fought which boosted the force of the allied power and helped the other allied powers greatly particularly economically meaning it was not(c) but the answer is (D).
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