Suppose the own price elasticity of demand for good X is -3, its income elasticity is 1, its advertising elasticity is 2, and the cross-price elasticity of demand between it and good Y is -4. Determine how much the consumption of this good will change if: a. The price of good X decreases by 5 percent. b. The price of good Y increases by 8 percent. c. Advertising decreases by 4 percent. d. Income increases by 4 percent.