A Scientist Attempts to Use the CRISPR-Cas9 System to Edit

A scientist attempts to use the CRISPR-Cas9 system to edit a single gene within a cell. She finds that, in addition to editing the desired gene, she has edited several other genes as well. What are reasonable options for her to try next in order to target just the gene of interest? (Select all that apply.)

A) Add less Cas9 enzyme.
B) Create a longer sgRNA.
C) Try a different sgRNA that will still pair within the gene of interest.
D) Use separate crRNA and tracrRNA molecules.
E) Use a higher-fidelity version of Cas9.