Up to Half of the IgG Found in the Serum

Multiple Choice

Up to half of the IgG found in the serum of a normal individual is produced by which of the following cells?

A) Naive B cells in lymph nodes
B) Activated B cells in the spleen
C) B cells in germinal centers of lymph nodes
D) B lymphocytes in the gastrointestinal tract
E) Long-lived plasma cells in the bone marrow