If a Perfectly Competitive Firm Produces at an Output Level

Multiple Choice

If a perfectly competitive firm produces at an output level where marginal cost equals marginal revenue,then

A) the last unit produced adds the same amount to costs as it does to revenue.
B) the firm is maximizing its revenue.
C) there is no reason to reduce or expand output,as long as AVC is greater than or equal to price.
D) the difference between TR and TC is zero.
E) the firm should shut down.