Which of the Following About Price Discrimination Is True

Which of the following about price discrimination is true?

A) A price-discriminating seller will charge consumers with an elastic demand a lower price than consumers with an inelastic demand.
B) A firm must face a horizontal demand curve for its product in order to engage in effective price discrimination in a market.
C) Price discrimination always harms consumers and helps sellers in the short run but in the long run, consumers benefit at the expense of sellers.
D) A seller must have a monopoly in order to gain from price discrimination.