In a perfectly competitive market, if firms are earning positive economic profits in the short run, new firms are drawn in since entry is free, which increases supply and drives price down until those profits are competed away. If firms are instead losing money, some exit the market, reducing supply and pushing price back up.
This ongoing process of entry and exit continues until, in long-run equilibrium, price settles exactly at average total cost and firms earn zero economic profit, though they still cover every cost, including a normal return on their investment, known as normal profit.
So option 1 is correct.