The market price of cheeseburgers in a college town increased recently, and the students in an economics class are debating the cause of the price increase. Some students suggest that the price increased because the price of beef, an important ingredient for making cheeseburgers, has increased.
Other students attribute the increase in the price of cheeseburgers to a recent increase in the price of calzones at local pizza parlors. Everyone agrees that the increase in the price of calzones was caused by a recent increase in the price of pizza dough, which is not generally used in making cheeseburgers.
Assume that burger joints and pizza parlors are entirely separate entities—that is, there aren't places that serve both cheeseburgers and calzones. The first group of students thinks the increase in the price of cheeseburgers is due to the fact that the price of beef, an important ingredient for making cheeseburgers, has increased.
Suppose that both of the events you analyzed above are partly responsible for the increase in the price of cheeseburgers. Based on your analysis of the explanations offered by the two groups of students, how would you figure out which of the possible causes was the dominant cause of the increase in the price of cheeseburgers?

a. If the equilibrium quantity of cheeseburgers increases, then the demand shift in the market for cheeseburgers must have been larger than the supply shift.

b. If the price increase was large, then the supply shift in the market for cheeseburgers must have been larger than the demand shift.

c. Whichever change occurred first must have been the primary cause of the change in the price of cheeseburgers.

d. If the equilibrium quantity of cheeseburgers increases, then the supply shift in the market for cheeseburgers must have been larger than the demand shift.