Answer:
A) making zero economic profit
Step-by-step explanation:
A perfectly competitive industry is where there are many firms producing homogenous goods and services. There are no barriers to entry or exit of firms. Prices are set by market forces. Buyers and sellers are price takers.
In the short run, if firms in a perfectly competitive market are earning economic profits, in the long run, new firms enter into the industry and economic profit falls to zero.
In the short run, if firms in a perfectly competitive market are earning economic loss, in the long run, firms leave the industry and economic profit goes up to zero.
I hope my answer helps you