Use the Figure Below to Answer the Following Questions

Use the figure below to answer the following questions.

Figure 19.3.2
-Refer to Figure 19.3.2. At an employment level of 40 hours per week, the difference in the value of marginal product of high-skilled workers and low-skilled workers is

A) $0.
B) $2 an hour.
C) $6 an hour.
D) $4 an hour.
E) $3 an hour.