What is the implication of the entry and exit assumption under perfect competition?

All of the above

The correct answer is option 4: All of the above

The entry and exit assumption applies primarily to perfect competition, where firms can freely enter or exit the market. This assumption has several key implications:

1. In equilibrium, no firm earns supernormal profit

   • If firms earn supernormal (economic) profit, new firms will enter the market, increasing supply and driving prices down until only normal profit remains.

2. In equilibrium, no firm incurs loss by remaining in production

   • If firms incur losses, they will exit the market, reducing supply and pushing prices up until remaining firms break even.

3. Equilibrium price will be equal to the minimum average cost of the firms

   • In the long run, firms produce at the minimum point of the average cost (AC) curve, ensuring productive efficiency.

Since all three statements are correct, the right answer is: All of the above.