When Individuals Have a Congenital Defect in Which They Lack

When individuals have a congenital defect in which they lack the CD40 ligand (CD40L) on activated T cells, the outcome of that defect is:

A) They are not able to make mature T or B cells
B) They are only able to make CD8 cells and no other types of T cells
C) They are only able to make IgM antibody and no other type of antibody
D) They are not able to any antibodies at all even though B and T cells are present