Pure competition is important to economists because it is . Pure competition is important to economists because it is . the lowest cost to the buyer the benchmark of efficiency to compare all other models against both a. and b. none of the above

a and b

Explanation:

A perfect or pure competition is characterized by many buyers and sellers of homogenous goods and services. Market prices are set by the forces of demand and supply. There are no barriers to entry or exit of firms into the industry.  

In the long run, firms earn zero economic profit.  If in the short run firms are earning economic profit, in the long run firms would enter into the industry. This would drive economic profit to zero.  

Also, if in the short run, firms are earning economic loss, in the long run, firms would exit the industry until economic profit falls to zero.  

Due to maximum competition in a pure competition, it is the lowest cost to the buyer.

Pure competition is efficient because, goods are priced at equilibrum