Answer:
The correct answer is option d.
Explanation:
In a perfectly competitive market, the firms produce at the point where price equals the marginal cost. If marginal cost is higher than the average total cost, it means the price level is also higher than average total cost. This shows that the firms will be having super normal profits.
Other potential firms will be attracted by these profits but they can't join in the short run. Though potential firms will enter the market in the long run.