51. Why can normal immune responses be described as polyclonal? (A) Blood contains many different antibodies to many different antigens. (B) Construction of a hybridoma requires multiple types of cells. (C) Multiple immunoglobulins are produced from descendants of a single B cell. (D) Diverse antibodies are produced for different epitopes of a specific antigen. (E) Macrophages, T cells, and B cells all are involved in normal immune response.