Which of the Following Statements Is True

Which of the following statements is true?

A) Discrimination can reduce the perceived marginal revenue products of some groups of workers and thus lower their wage.
B) Between 1975 and 1997, there was a considerable reduction in the gap between white male wages and black male wages.
C) The average wage of black females has risen to about 80 percent of the average wage of white males.
D) The gap between the earnings of black women and white males is smaller than the earnings gap between black males and white males.