Jane Mattock, CFA, senior vice president and head of the research department of H&V, Inc., a regional brokerage firm. In preparation for a long business trip, Mattock delegates his authority to Deion Miller, CFA. Which of the following is most accurate to comply with the Professional Conduct Standards（）
A. Mattock is required to advise his supervisor and his compliance department, in writing, of the delegation of his supervisory duties.
B. Mattock still has supervisory responsibility and must instruct Miller about methods to prevent and detect violations of applicable laws, rules, regulations, and the CFA Institute Code of Ethics and Standards of Professional Conduct.
C. Miller still has supervisory responsibility but need not instruct a charterholder like Miller about methods to prevent and detect violations of applicable laws, rules, regulations, and the CFA Institute Code of Ethics and Standards of Professional Conduct.