CRISPR-Cas9, a prokaryotic defense mechanism, is a powerful emerging tool in biotechnology for all of the following EXCEPT

A) allowing the editing of defective genes in eukaryotic cells.
B) introducing insertions, deletions, or sequence modifications into a given genome with CRISPR-Cas9.
C) regulating gene expression in bacteria with CRISPRi, in which case Cas9 is no longer active as a nuclease.
D) marking a defective gene with antibiotic resistance.
E) disrupting latent HIV provirus in infected cells.