May I please get some help with this question? No further information is provided, aside from the attached screenshot.

A firm is a natural monopoly if O A. any entrant would have the same costs. O B. its profit does not increase with output. O C. one firm can produce the total output of the market at lower cost than two or more firms could. O D. it has no fixed costs. O E. its marginal revenue is increasing faster than average costs