Suppose a Firm Has Two Plants Producing the Same Good

Multiple Choice

Suppose a firm has two plants producing the same good.Each plant is producing 200 units of the good.In plant A,the short run average cost of production is $20 and in plant B it is $30.If the firm wants to produce a total of 400 units at the lowest cost in the long run,it should:

A) switch production from plant B to plant A until the average cost of production at each plant is the same.
B) produce only at plant A and shut down plant B.
C) switch production from plant B to plant A until the average cost is the same at the two plants.
D) continue to use the same input ratio.