Which of the following statements about U.S. racial categories is true?

Which of the following statements about U.S. racial categories is true?
 
  A. U.S. racial categories are applied to endogamous breeding populations.
  B. U.S. racial categories are biologically valid, as demonstrated by the Phipps case in the 1970s in Louisiana.
  C. U.S. racial categories are based on global racial categories that vary little among societies.
  D. U.S. racial categories are based on genetics, whereas Japan's are based upon undemonstrated descent.
  E. U.S. racial categories are culturally arbitrary, even though most people assume them to be based in biology.