Final answer:
A monopolistic competitor can calculate its profits in the short run by subtracting total costs from total revenue.
Step-by-step explanation:
The profits of a monopolistic competitor in the short run can be determined by calculating the difference between total revenue and total cost. The firm will charge a price that the market is willing to pay based on the profit-maximizing quantity and the demand curve. The total revenue is calculated by multiplying the quantity sold by the price, while total costs are calculated by multiplying the quantity by the average cost. By subtracting total costs from total revenue, the firm can determine its profits.
In the given information, the firm's total revenue is $4000 and the total cost is $1650. Therefore, the firm's profits would equal $4000 - $1650 = $2350. Therefore, none of the given options (A. -$55, B. $0, C. $250, D. $280) accurately represents the firm's profits in the short run.