Answer:
A. product differentiation
Step-by-step explanation:
Product differentiation is making a good or service different from that of compettitors in order to attract customers.
Equilibrium price is the price at which the demand curve is equal to the supply curve.
a monopsony is where there's only one buyer in the market.
A perfectly competitive market is when there are many buyers and sellers of homogenous goods and services.
I hope my answer helps you