Which of the following statements concerning B cell receptors (BCRs) is FALSE?

A) They are formed in response to an encounter with an antigen.
B) They are complementary in shape to a specific antigenic determinant that they may or may not encounter.
C) They are bound to the surface of B lymphocytes and have two antigen-binding sites.
D) Each B lymphocyte is randomly generated with antibody variable regions that determine its BCR.
E) Scientists estimate that each person forms at least 10¹¹ different types of B lymphocytes with distinct BCRs.