To determine an appropriate congestion tax, an economist has to assume that people respond to incentives

Which of the following statements is true?

a. If the income elasticity of demand is less than zero, the good is an inferior good. b. Only if the demand curve is vertical will sellers raise the price by the full amount of a tax. c. Two goods are substitutes if the cross-elasticity of demand coefficient is positive. d. A price elasticity of supply coefficient equal to 1.5 means the product exhibits an elastic supply and a 10 percent increase in the price will increase the quantity supplied by 15 percent. e. All of these.

If Mario's Pizza offers consumers who purchase one medium sized pizza a second pizza at half price, this is an example of ________.

A) third-degree price discrimination B) second-degree price discrimination C) first-degree price discrimination D) zero-degree price discrimination