20. CRISPR/Cas9 is the most talked about technique in the past few years for targeted genome editing. Which of the following statement about CRISPR/Cas9 is incorrect? (A) Cas9 is an endonuclease that cut double-stranded RNA. (B) An RNA molecule guides Cas9 to the target. (C) The system has been shown to work in many organisms including fish, yeast and plants. (D) The system was originally discovered as part of adaptive immunity in bacteria.