Answer:
B. No, no free entry
Step-by-step explanation:
With a patent granted to one pharmaceutical company to produce and sell an experimental AIDs drug, all doors of free entry and exit have been locked against other pharmaceutical companies. This implies that one of the major ideals of a competitive market is violated. Without free entry and exit, there cannot be many sellers, and we cannot discuss about the possibility of firms producing identical products because there is only one drug.