There Is a Mutation in the Gene for CD4 in a Helper

Multiple Choice

There is a mutation in the gene for CD4 in a helper T cell such that it is transcribed and translated,but it cannot bind to class II MHC molecules.What effect will this have on the adaptive immune response?

A) Histamine would not be produced at all.
B) Cytotoxic T cells would not be as effective as normal.
C) Antibodies would not be produced as readily.
D) Lymphocytes would not differentiate as quickly.