Answer:
The correct answer is option d. "Polyclonal antibodies".
Step-by-step explanation:
The enzyme-linked immunosorbent assay (ELISA) is very useful in comparison to other immunoassay methods for being highly accurate, sensitive and specific. Polyclonal antibodies for the detection step could be used on order to ensure that a mutation in a single surface protein would not make obsolete an ELISA used to detect a new viral pathogen. Unlike monoclonal antibodies, polyclonal antibodies are a collection of antibodies that recognize multiple epitopes of the same antigen. Therefore, a mutation in one epitope that affects the binding of one antibody would not affect the bind of the others and the ELISA will be able to recognize the pathogen.