The large number of antibodies that can be produced in a single individual is a result of a single B cell: producing multiple unique antibodies by genomic rearrangement. being able to produce unique antibodies from both the maternal and paternal alleles. producing a unique antibody from all other B cells by genomic rearrangement. secreting multiple antibodies that will be presented on the surface of other B cells.

The answer is; producing a unique antibody from all other B cells by genomic rearrangement.

An isolated B cell produces monoclonal antibodies (also called Immunoglobulins). Different B cell types produce different types of antibodies (hence the serum of an animal has polyclonal antibodies). Memory B cells are developed when a particular infection is eradicated by the immune system. These B cells proliferate when the infection returns by producing the same antibodies that were effective against the foreign entity.