Answer:
option B
Perfect competition and monopoly
Step-by-step explanation:
A perfect competition market describes an arrangement where there exists man buyers and sellers trading an identical goods for which neither the buyers nor the seller can exercise significant market power. The buyers cannot influence the price and the sellers also cannot influence the price .
On the contrary , a monopoly is a market structure where there exist a singe seller/producer of product, with many buyers, for which there is no substitute product. Therefore the seller or producers exist a significant market power.
Perfect competition and monopoly