Answer: Option (b) is correct.
Explanation:
Correct Option: Licenses
In United States, there is a licensing system which prohibits the number of taxicabs allowed. So, there are less number of taxicabs companies operates in most of the united states cities.
There is a advantage for the taxicabs companies for using the monopoly power.
Whereas, some of the cities of U.S use 'taxi medallions" as the permits for picking up the passengers.
