Table 141 Incomes in Pololand -Which of the Following Is Not a Major Cause of l

Table 14.1 Incomes in Pololand
$$\begin{array} { l l l l l } & \text { Period 1 } & \text { Period 2 } & \text { Period 3 } & \text { Period 4 } \\\hline \text { Thomas } & \$ 50,000 & \$ 40,000 & \$ 60,000 & \$ 100,000 \\\text { Nina } & \$ 40,000 & \$ 40,000 & \$ 40,000 & \$ 80,000 \\\text { Becky } & \$ 30,000 & \$ 30,000 & \$ 30,000 & \$ 60,000 \\\text { Rose } & \$ 20,000 & \$ 20,000 & \$ 20,000 & \$ 40,000 \\\text { Charlie } & \$ 10,000 & \$ 20,000 & \$ 0 & \$ 20,000 \\\hline\end{array}$$
-Which of the following is not a major cause of the increase in the inequality since 1980?

A) increased returns to investments in higher education
B) increased earnings disparities within human-capital groups
C) the change in female relative to male earnings since 1980
D) decrease in the price of high-tech goods