Working women in the United States earn only three-quarters of what men earn. Consider each of the following explanations for this statistic, and say whether each could be true or must not be true in order to explain this fact.
a. Women choose lower-paying professions (e.g., becoming a nurse rather than a doctor).
b. Women are discriminated against when being considered for promotions or raises.
c. Women are more educated and have more work experience than men, on average.
d. Women are discriminated against in the hiring process.
e. Women benefit from affirmative action in the hiring process.