The answer I have selected may or may not be correct. Please verify.

A perfectly competitive constant-cost industry is initially in long-run equilibrium. When the demand for the industry's product increases, which of the following will occur? O A. The price of the product will increase in the long-run. O B. Firms will earn positive economic profits in the short-run. O C. New firms will enter the market. O D. The price of the product will increase in the short-run