A Mouse Is Immunized with the Tetanus Toxoid Protein (Inactivated

A mouse is immunized with the tetanus toxoid protein (inactivated toxin) in adjuvant. One week later, the entire population of splenic B cells are isolated from the mouse and mixed with tetanus toxoid-specific CD4 T_FH cells plus the purified tetanus toxoid protein. Four days later, the total number of B cells in the culture and the number of tetanus toxoid-specific B cells are determined and compared to the starting population on the day of isolation. The results are shown in Figure Q1) . B cells preferentially survive and proliferate because:

A) They are the only B cells that express CD40.
B) They are the only B cells that express the receptor for IL-21.
C) They are the only B cells that proliferate in response to their antigen.
D) They are the only B cells presenting the tetanus peptide to the T_FH cells.
E) They are the only B cells that received a TLR stimulus during priming.