QUESTION $11$

Use the diagram below to answer the question below:

Assuming that the curves above are representative of an inferior good, which of the following could explain a movement from point $\backslash ($ p$\_\{1\}$ q$\_\{2\}\backslash )$ to point $\backslash ($ p$\_\{1\}$ q$\_\{1\}\backslash )$ in the figure?

a$)$ an increase in the price of a complement

b an increase in buyers' income

c$)$ a decrease in the buyers income

d$)$ an increase in the price of the good