Viral Neutralization Testing Is Based on the Fact That

Viral neutralization testing is based on the fact that

A) antibodies to certain microbes can be given a fluorescent label.
B) antibodies have different molecular weights.
C) antibodies can be produced against the toxin of a pathogen.
D) the gene for a pathogen's antigen can be isolated and introduced into a host cell by way of a plasmid.
E) viruses introduced into appropriate cell cultures have a cytopathic effect.