The Selective/clonal Selection Theory of Immune Response Ultimately Proved to Be

The selective/clonal selection theory of immune response ultimately proved to be correct, but the instructional theory, while incorrect, seemed logical because

A) if thousands of preformed antibodies were present to antigens that are never encountered, this is excessively wasteful and poor use of the body's resources.
B) the immune system was shown to be capable of such a wide variety of substances that it seemed impossible that such a high number of different possibilities would be preformed without any prior exposure.
C) if one gene produces one antibody, then it didn't seem that humans had enough DNA to produce thousands of possible antibodies.
D) it seemed reasonable that a cell would be "instructed" to react to a specific antigen only when it was encountered.
E) All of the above.