Which of the following is a duty of the Board of Governors of the Federal Reserve​ System? A. Regulating credit with the approval of the president under the Credit Control Act of 1969. B. Setting margin​ requirements, the fraction of the purchase price of the securities that has to be paid for with cash. C. Setting the maximum interest rates payable on certain types of time deposits under Regulation Q. D. All governors advise the president of the United States on economics policy.