Final answer:
In short, perfectly competitive firms can earn economic profits in the short run but not in the long-run equilibrium. They aim to maximize total profit, and sometimes maximizing profit aligns with minimizing losses. The long-run market supply curve can have various slopes.
Step-by-step explanation:
The statement a. Perfectly competitive firms can never earn economic profit is FALSE. In the short run, perfectly competitive firms can earn economic profits. However, in the long-run equilibrium, economic profits tend to be zero because new firms will enter the market when existing firms are making profits, increasing supply and driving down prices until profits are eliminated.
The statement b. Perfectly competitive firms seek to maximize both per-unit and total profit is TRUE. Firms always aim to maximize profits, but in a perfectly competitive market, the per-unit profit is dictated by the market price which the firm has no power to influence. Total profit is maximized when the difference between total revenue and total cost is the greatest.
Regarding statement c. Sometimes, profit-maximization is the same as loss-minimization, this is TRUE. In scenarios where firms cannot cover their total costs, they will seek to minimize losses by producing until marginal revenue equals marginal cost, which is also the profit-maximizing condition.
The statement d. Long-run market supply curves are always upward-sloping is FALSE. The slope of the long-run market supply curve can be upward, downward, or even horizontal, depending on the changes in production costs and entry or exit of firms in the market.