which one should i choose

Many car owners and car dealers describe their different cars for sale in the local newspapers

and list their asking price. Many people shopping for a used car consider the different choices

listed in the paper. The absence of which condition prohibits this market from being

described as perfectly competitive?

A) Buyers and sellers know the prices.

B) Firms freely enter and exit.

C) Transaction costs are low.

D) Consumer believes all firms sell identical products.