Final answer:
The enforceable part of the AICPA's Code of Professional Conduct is the 'Rules.' These standards are designed to maintain high ethical conduct among its members.
Step-by-step explanation:
Of the four parts of the AICPA's Code of Professional Conduct, the part that is enforceable is b. Rules. These rules are designed to ensure that the highest standards of professional and ethical conduct are maintained by its members. Unlike the principles, which are aspirational, the rules are specific standards that can lead to disciplinary action if violated. Professional organizations like the Institute of Electrical and Electronic Engineers Computer Society (IEEE-CS) also have similar codes of ethics for their members, illustrating the importance of established ethical standards across various professions.