The genes for proteins such as b-galactosidase (lacZ) or green fluorescent protein (gfp) can be fused to the promoter of a gene of interest. Which of the following statements is NOT correct about gfp and lacZ?

A) They are called reporter genes.
B) The enzymatic activity of b-galactosidase can be easily assayed.
C) GFP is visualized by fluorescence microscopy.
D) Both genes are of viral origin.
E) The gfp gene is of eukaryotic origin, whereas lacZ is a bacterial gene.