Why is the calculation of profit different in a monopoly compared to perfect competition?

• A. In a monopoly, profit is calculated using total cost instead of average total cost.
• B. In a monopoly, marginal revenue is less than price, unlike in perfect competition where they are equal.
• C. In a monopoly, the demand curve is horizontal, unlike in perfect competition.
• D. In a monopoly, average total cost is always higher than in perfect competition.

Answer: (B)