Which Is Not True of Price Discrimination

Which is not true of price discrimination?

A) It exists when price differences depend critically on different buyers' evaluations of a product.
B) Successful price discrimination will provide the firm with more profit than if it does not discriminate.
C) Successful price discrimination implies that the producer can separate customers into easily identifiable groups.
D) Successful price discrimination will generally result in a lower level of output than would be the case under a single-price monopoly.