Place the following events in the order they occur by listing their assigned letters in that order. A. Cas9 REC domains binds to the guideRNA B. Cas9 complex binds to dsDNA C. Cas9 complex scans dsDNA for PAM sequence D. Cas9 unwinds dsDNA E. The programmable part of the guideRNA binds to its complementary sequence F. Cas9 cuts both strands to generate a double strand break