Consider a beekeeper who produces honey and sells it at a constant price per kilogram. Assume that the marginal private cost of producing honey increases with output, and that there is a neighbouring farmer whose crops the bees can help pollinate. Which of the following statements is correct? Select one: O a. The beekeeper's marginal private benefit (MPB) curve is upward sloping. O b. None of the listed answers is correct. O c. There is a marginal external cost of producing honey. O d. The beekeeper's profit-maximising output level is lower than the Pareto-efficient level. O e. The marginal social benefit (MSB) curve will be below the MPB curve