This topic investigates the establishment and implementation of information wall system in securities companies. According to the Guidelines for Information Wall System of Securities Companies, the specific responsibilities of the board of directors, management, business departments and branches, staff, compliance director and compliance department are as follows: 1. The main person in charge of the board of directors and management of securities companies is the ultimate person in charge of the overall effectiveness of the company's information wall system; Options c and d include. 2. The heads of all business departments and branches are responsible for the effective management of the information wall system implemented by their own departments and institutions; A options include. 3. The staff of securities companies are directly responsible for observing the information isolation system in their practice activities; 4. The Compliance Director and Compliance Department are responsible for assisting the Board of Directors and the management to establish information barrier related systems, and are responsible for review, supervision, inspection, consultation and training; The supervisor does not belong to the subject who needs to bear the responsibility. So option b does not include. So choose option b in this question.