If the cross-price elasticity between ketchup and hamburgers is 1.5, a 2 percent decrease in the price

Question:

If the cross-price elasticity between ketchup and hamburgers is −1.5, a 2 percent decrease in the price of ketchup will lead to a:
a) 3 percent increase in quantity demanded of ketchup.
b) 3 percent decrease in quantity demanded of ketchup.
c) 3 percent increase in quantity demanded of hamburgers.
d) 3 percent decrease in quantity demanded of hamburgers.