Final answer:
A perfectly competitive firm should continue to produce in the short run if the price is greater than the average variable cost at the quantity where marginal revenue equals marginal cost.
Step-by-step explanation:
A perfectly competitive firm maximizes its profit by producing at the quantity of output where marginal revenue (MR) equals marginal cost (MC). If at that quantity, the price is greater than the average variable cost (AVC), the firm should continue to produce in the short run. This is because the firm is covering its variable costs and making a contribution towards its fixed costs. If the price is less than the AVC, then the firm should shut down its operation in the short run, as it will not even be covering its variable costs.