Which of the Following Is Not an Explanation for Why

Multiple Choice

Which of the following is not an explanation for why better educated workers earn more, on average, than less educated workers?

A) The higher wages may be a compensating differential for the cost of acquiring the education.
B) Workers with a college degree signal their higher abilities to potential employers.
C) Skilled labor is increasingly becoming a substitute for unskilled labor, which raises the earnings of workers with more education.
D) Better educated workers are more productive, on average.