Calculate the cross-price elasticity for the following goods. Determine if they are substitutes or complements?
A. The price of airline tickets goes up by 20 percent, causing the quantity demanded for gasoline to go up by 5 percent.
B. The price of pancake flour goes up by 10 percent, causing the quantity demanded for pancake syrup to drop by 20 percent.
C. The price of coffee goes up by 5 percent, causing the quantity demanded for tea to increase by 5 percent.
D. The price of computers goes up by 5 percent, causing the quantity demanded for flash drives to drop by 2 percent.