Which of the Following Statements Is True

Which of the following statements is true?

A) Under monopoly, the seller sets the price of its good below marginal costs.
B) Under perfect competition, sellers set the price of their goods below marginal costs.
C) Under monopoly, prospective buyers may not be able to buy a good even if they have a willingness to pay above marginal costs.
D) Under perfect competition, prospective buyers may not be able to buy a good even if they have a willingness to pay above marginal costs.