Refer to the Above Diagram,which Shows Demand and Supply Conditions

Refer to the above diagram,which shows demand and supply conditions in the competitive market for product X.A shift in the demand curve from D₀ to D₁ might be caused by a(n) :

A) decrease in income if X is an inferior good.
B) increase in the price of complementary good Y.
C) increase in money incomes if X is a normal good.
D) increase in the price of substitute product Y.