How Did the Struggle Against Nazi Tyranny Discredit Racial Inequality

How did the struggle against Nazi tyranny discredit racial inequality in the United States?

A) Germany's Nazi leaders, it turned out, had entertained a romanticized fascination with the Confederacy.
B) African-Americans had borne the brunt of the fight against German troops and demonstrated that they were the "master race."
C) The exceptional cruelty American soldiers exercised against Germans had sobered Americans on the idea that they were a "master race."
D) The contradictions between the principle and practice of freedom in the actual status of African-Americans came to the forefront during the war.
E) American soldiers had universally demonstrated restraint and civility in their combat operations against their enemies, especially in the Pacific.