Final answer:
A profit-maximizing firm in a perfectly competitive market will employ resources to the point where marginal revenue product is at least as much as the marginal resource cost (MRP >= MRC), and it will produce at the output level where marginal cost equals price (P = MC).
Step-by-step explanation:
A profit-maximizing firm employs resources to the point where marginal revenue product (MRP) is greater than or equal to marginal resource cost (MRC), which aligns with option C. In other words, the firm will hire resources as long as the additional revenue generated by those resources is at least as much as the cost to hire them.
For a perfectly competitive firm, the profit-maximizing rule is to produce at the quantity of output where the price of the product (P) equals the marginal cost (MC) of production, which signifies where MR = MC. This is because, in perfect competition, the marginal revenue received by the firm is equal to the price of the product.
The profit-maximizing level of output for such a firm occurs where MR = MC, which is not to be confused with the non-competitive markets where MR does not equal the price due to the effect of output quantity on price.