Which of the Following Is an Example of a Barrier

Multiple Choice

Which of the following is an example of a barrier to entry? (i)
A key resource is owned by a single firm.
(ii)
The costs of production make a single producer more efficient than a large number of producers.
(iii)
The government has given the existing monopolist the exclusive right to produce the good.

A) (i) and (ii) only
B) (ii) and (iii) only
C) (i) only
D) (i) , (ii) , and (iii)