If a perfectly competitive firm finds that price is greater than AVC but less than ATC at the quantity where its marginal cost equals the market price,

a. the firm will produce in the short run but may eventually go out of business.

b. the firm will produce in the short run, and new entrants will tend to enter the industry over time.

c. the firm will immediately shut down.

d. the firm will be earning economic profits.

e. both b and d are true.