The correct option is C Monoclonal antibodies
Monoclonal antibodies are monospecific antibodies that are made by identical immune cells that are all clones of a unique parent cell. In 1975, Georges Kohler and Cesar Milstein succeeded in making fusions of myeloma cell lines with B cells to produce hybridomas that made antibodies to known antigens. Monoclonal antibodies were first produced by applying the techniques of somatic cell genetics to antibody-producing cells. The cells that produce antibodies (B cells) are short-lived in culture. Thus, attempts to maintain B cells in culture and harvest antibody specificities failed for many years until Cesar Milstein and George Koehler succeeded in immortalising B cells via somatic cell hybridisation.