The Fact That B Cells and T Cells Are Both

The fact that B cells and T cells are both clonally selected means that

A) each individual can form many different antibodies, but only one type of T cell receptor.
B) there are five different types of immunoglobulin.
C) each B cell or T cell produces only one kind of antibody.
D) B cell lymphocytes change their antibody specificity to match a newly discovered antigen, and then undergo mitosis to form a clone of plasma cells.
E) antibodies and T cell receptors are made before exposure to antigen.