According to the clonal selection theory
A. antibodies are modified, at the time of antigen exposure, to specifically react with the antigen.
B. self-reactive T cells are killed in the thymus.
C. B cells producing autoantibodies are eliminated in the thymus.
D. each B cell is already programmed to produce a specific antibody.
E. self reactive T cells are killed in the thymus AND B cells producing autoantibodies are eliminated in the thymus.