Which Statement Best Describes Why an Individual's Antibodies and T

Which statement best describes why an individual's antibodies and T cells do not attack their own cells?

A) B and T cells have about 100,000 antigen receptors and so they can match anything in the human body.
B) Interferons interfere with antibodies trying to attach to the B and T cells
C) Opsonins keep leukocytes from binding to the B and T cells
D) B and T cells mature in the bone marrow and thymus; their antigen receptors are, in effect, tested for their potential to recognize and react against self.
E) B and T cells develop into plasma cells which dissolve automatically into the plasma, thus they are not recognized as foreign.