Answer
D
Work Step by Step
For activation of B cells to occur, the antigen must bind to B cell receptors (BCR). Then, the B cell receptor mediated endocytosis occurs in which antigen is internalized and digested and is presented on MHC type 2 molecule. It is recognized by T helper cells which bind to B cells and produce cytokines. Then the cytokines stimulate B cells to produce antibodies. The cytotoxic T cells do not play any role in activating B cells.