Option 1 During development T cells undergo both positive selection and negative selection, while B cells undergo only negative selection (by apoptosis of self-reacting immature B-cells in spleen). Death of cells with TCRs that do not react with self MHC proteins - negative selectionSurvival of cells with TCRs that react with self MHC preoteins- positive selection Option 2 MHC class I Present on All nucleated cells (except sperms) and platelets. Option 3 Both cells have Antigen Specific Receptors. FIGURE 01:Development of T cells. Note the positive and negative selection that occurs in the thymus. Maturation of B cells- Cells arise from stem cells and differentiate into pre-B cells expressing m heavy chains in the cytoplasm and then into B cells expressing monomer IgM on the surface. This occurs independent of antigen. Activation of B cells and differentiation into plasma cells is dependent on antigen. Cells to the left of the veical dotted line do not have IgM on their surface, whereas B cells, to the right of the veical line, do have IgM. m, mu heavy chains in cytoplasm; Y, IgM.