The _______ Contribute to Antigen Specificity of Immunoglobulins,and _______ Make

The _______ contribute to antigen specificity of immunoglobulins,and _______ make up the more conservative flanking regions.

A) hypervariable loops; framework regions
B) constant domains; variable domains
C) heavy chains; light chains
D) variable gene segments; joining gene segments
E) antigenic determinants; complementarity determining regions.