All of the Following Except One Are Necessary Conditions in Order

Multiple Choice

All of the following except one are necessary conditions in order for price discrimination to be practiced.Which is the exception?

A) The different groups of buyers must have different elasticities of demand.
B) The seller's costs of production must be different in reference to each group of buyers.
C) The seller must be able to identify members belonging to different buying groups.
D) The seller must be able to separate members belonging to different buying groups.
E) The seller must be able to prevent the resale of the product.