Which of the following would an economist consider a barrier to entry?
a. Pamela cannot earn enough as an Uber driver to cover her expenses.
b. Harrison's documentary films are hard to watch and unpopular with audiences.
c. Miles has to pass the state bar exam before he can open a law practice.
d. Bad weather has caused delays with Brad's gardening store opening.
e. Mia must finish a project before she can leave her current job to start her own firm.