If a Firm in a Perfectly Competitive Market Faces the Curves

If a firm in a perfectly competitive market faces the curves in the graph shown and observes a market price of $16, the firm:

A) can earn positive profits by producing less than 43 units.
B) can earn positive profits by producing where marginal cost equals marginal revenue.
C) cannot make positive profits and should shut down in the short run.
D) should continue to operate in the short run, but plan to exit in the long run.