All of the Following Conditions,except One,must Exist in Order for a Firm

Multiple Choice

All of the following conditions,except one,must exist in order for a firm to successfully practice price discrimination.Which is the exception?

A) The firm must be a price taker.
B) The firm must be able to identify which customers are willing to pay more.
C) The firm must be able to prevent the resale of its output by low-price customers to high-price customers.
D) The firm must be able to charge higher prices to some customers without losing their business.
E) The firm must be a price setter.