Refer to the Information Provided in Figure 13

Refer to the information provided in Figure 13.1 below to answer the questions that follow. Figure 13.1
-Refer to Figure 13.1. Which of the following can change the equilibrium wage rate from $9 to $6?

A) The value people put on their leisure time increases.
B) The value of what firms produce increases.
C) The productivity of workers decreases.
D) The productivity of workers increases.