Which of the Following Statements About Discrimination Is True

Which of the following statements about discrimination is true?

A) The effects of discrimination can be illustrated through supply and demand by shifting the supply curve.
B) Competitive markets lead to discrimination by allowing employers freedom to hire and fire at will.
C) Wage differences among different groups in society cannot be fully explained by productivity and experience.
D) The fact that women are paid 70 percent of what men are paid is proof of gender discrimination.
E) During the 1980s, the average pay gap between men and women increased.