Which One of the Following Statements About Humoral Immune Responses

Which one of the following statements about humoral immune responses is true?

A) Naive B cells are required for initiation of primary responses and memory B cells are required for initiation of secondary responses.
B) Antibody responses to bacterial polysaccharide antigens require CD4⁺ helper T cells.
C) Heavy chain isotype switching typically occurs in response to bacterial polysaccharide antigens.
D) Affinity maturation does not require helper T cells.
E) Antibody-secreting cells generated during a humoral immune response live for only a few hours.