In the Above Figure, the Shift in the Demand Curve

Multiple Choice

In the above figure, the shift in the demand curve from D to D1 can be the result of

A) an increase in the price of soft drinks, a complement to pizza.
B) an increase in the price of pizza.
C) a change in quantity demanded.
D) an increase in the price of a sub sandwich, a substitute for pizza.
E) a decrease in income if pizza is a normal good.