What Best Explains the Increased Attention the Federal Government Paid

What best explains the increased attention the federal government paid to the problem of racial discrimination during the 1940s?

A) The NAACP had successfully lobbied members of Congress for better federal legislation against disenfranchisement.
B) Northern migration of African Americans increased their voting strength.
C) The fight against the Nazis challenged the assumptions of white supremacy.
D) The ratification of the Fourteenth Amendment forced the federal government to act on racial discrimination.