Which of the Following Statements Is One of the Assumptions

Which of the following statements is one of the assumptions of the theory of perfect competition?

A) Firms produce a wide variety of versions of the product.
B) Firms are price setters.
C) Consumers know the prices charged by each firm.
D) A firm's entry to the market is regulated by the federal Competition Bureau.
E) Firms compete with each other by varying their price.