Which of the Following Is a Reason Why the Wage

Which of the following is a reason why the wage rate of high-skilled workers exceeds the wage rate of low-skilled workers?

A) The market for high-skilled workers is more competitive than the market for low-skilled labor.
B) The demand for high-skilled workers exceeds the demand for low-skilled workers.
C) The number of high-skilled workers exceeds the number of low-skilled workers.
D) Low-skilled workers often are in the process of acquiring more human capital.