Which of the Following Statements Accurately Describes Antibodies

Which of the following statements accurately describes antibodies?

A) Kappa and lambda are the two types of immunoglobulin heavy chains.
B) Genes coding for antibody constant regions undergo somatic recombination to generate diversity.
C) Antigens are always proteins that are exposed on the surface of foreign invaders.
D) Antigen-binding sites are located at the tips of the two arms of the Y-shaped antibody.
E) The variable region segments (V genes) are only subjected to somatic recombination to contribute to different antigen recognition as they come in direct contact with antigens.