What can you conclude about the price elasticity of demand in each of the following statements?
a. "The pizza delivery business in this town is very competitive. I'd lose half my customers if I raised the price by as little as 10%."
b. "I owned both of the two Jerry Garcia autographed lithographs in existence. I sold one on eBay for a high price. But when I sold the second one, the price dropped by 80%."
c. "My economics professor has chosen to use the Krugman/Wells textbook for this class. I have no choice but to buy this book."
d. "I always spend a total of exactly $10 per week on coffee."