4-21 (OBJECTIVES 4-5, 4-7) Each of the following situations involves a possible violation of the AICPA Code of Professional Conduct. For each situation, state the applicable rule of conduct and whether it is a violation. a. Sean Xi Lin, CPA, provides tax compliance services, secretarial services, and book- keeping services and also conducts audits for the same private company. b. Debbie Lakmaya, CPA, sells life insurance to the accounting staff of her client. c. A university professor publishes case studies on auditing based actual cases of his audit clients when he was working as an auditor in a CPA firm. The former clients are not in the know of this professor's actions