Apple's dominance of smartphone and tablet markets has allowed the firm to lock up 60 percent of the world's supply of advanced touch-screen displays, and to do so with better pricing than would be available to smaller rivals. this is an example of:
a. network externalities that make apple valuable.
b. high switching costs for suppliers.
c. a complex tech product establishing itself as a killer brand.
d. a growing firm gaining bargaining power with its suppliers.
e. low search costs associated with a famous brand.

Many potential buyers value high-quality used cars at the full-information market price of € p1 and lemons at € p2. a limited number of potential sellers value high-quality cars at € v1 ≤ p1 and lemons at € v2 ≤ p2. everyone is risk neutral. the share of lemons among all the used cars that might be potentially sold is € θ . suppose that the buyers incur a transaction cost of $200 to purchase a car. this transaction cost is the value of their time to find a car. what is the equilibrium? is it possible that no cars are sold