Mrs. Smith operates a business in a competitive market. The current market price is $8.10. At her profit-maximizing level of production, the average variable cost is $8.00, and the average total cost is $8.25. Mrs. Smith should

A、continue to operate in the short run but shut down in the long run.;
B、shut down her business in the short run but continue to operate in the long run.;
C、continue to operate in both the short run and long run.;
D、shut down in both the short run and long run.