Suppose That We Illustrate Demand and Supply with Quantity on the Horizontal

Multiple Choice

Suppose that we illustrate demand and supply with quantity on the horizontal axis and income on the vertical axis. Let demand be a function of price and income, Q^d (P, I) . Which of the following statements is true?

A) A change in income will cause a shift in the demand curve.
B) A change in income level is represented by a movement along the demand curve.
C) Income is treated as an exogenous variable in the graphical analysis.
D) Price and income together must change in order to create a shift in the demand curve.