Why Do Economists Study Perfectly Competitive Markets Even Though Few,if

Why do economists study perfectly competitive markets even though few,if any,markets in the real world are perfectly competitive?

A) Because insights we gain from studying the perfectly competitive market are directly applicable to real markets, even though they are not perfectly competitive.
B) Because the behavior of buyers and sellers can be studied theoretically only in the perfectly competitive market model.
C) Because the perfectly competitive market is a good approximation to many markets in the real world and helps us understand how real markets work.
D) Because the perfectly competitive market is the most relevant model for actual government economic policies.