Which of the following statements is true?
A. When monopoly is in equilibrium the price of its product will always equal the minimum possible Average cost of production
B. When a perfectly competitive industry is in the long-run equilibrium new firms will have incentive to enter the industry
C. When a perfectly competitive industry is in long run equilibrium firms in the industry will earn zero economic profit
D. When a perfectly competitive industry is in long-run equilibrium firms in the industry will earn positive economic profit
Answer: C