Which of the following statements best captures the so-called “shut down rule” for a monopolist that is able to engage in perfect price discrimination?

A. Shut down unless total revenue equals exceeds average fixed costs.

B. Shut down if average revenue is less than average variable cost.

C. Offer a product for sale, but only if marginal costs are less than marginal revenue.

D. Shut down unless there is some level of output that will generate positive economic profits

E. None of the above statements expresses the shutdown rule for a monopolist.