Which of the following four-firm concentration ratios would be the best indicator of an oligopoly?

The conclusion arrived at from a kinked-demand oligopoly model is that:

a. oligopoly firms cannot maximize their profits. b. oligopoly firms should keep prices at their current level. c. all oligopoly firms should raise prices. d. all oligopoly firms should lower prices. e. oligopoly market structure will lead to lower prices than more competitive industries.

Which of the following would shift the demand curve for gasoline to the right?

a. a decrease in the price of gasoline b. an increase in consumer income, assuming gasoline is a normal good c. an increase in the price of cars, a complement for gasoline d. a decrease in the expected future price of gasoline