Final answer:
A characteristic of a form of organization for a CPA firm under AICPA rules is that a majority of ownership must be held by CPAs.
Step-by-step explanation:
Under the AICPA's form of organization and name rule and the related resolution of the AICPA Council, one characteristic of a form of organization in which a member may practice public accounting is that a majority of the ownership of the firm must belong to CPAs. This stipulation ensures that those holding a controlling interest in the firm are licensed professionals adhering to the ethical and professional standards of the accounting profession. It is worth noting that other forms of business organizations are available, such as sole proprietorships, partnerships (including general partnerships where owners share responsibility and profits), and corporations, which provide different levels of liability protection and organizational structure. However, when it comes to public accounting firms, the AICPA places particular emphasis on professional licensure as a key component of ownership.