Final answer:
A CPA cannot disclose a client's confidential information when interviewed by a journalist (option 3). Professional ethics and laws restrict CPAs from revealing such information without client consent or legal requirements, despite the concept of reporter's privilege.
Step-by-step explanation:
A CPA (Certified Public Accountant) can NOT disclose a client's confidential information under several circumstances. However, based on the context provided, the specific situation in which a CPA must not disclose confidential information is when the CPA is interviewed by a journalist regarding a client's recent acquisitions (option 3). Even if the journalist offers reporter's privilege, a CPA is bound by professional ethics and laws that override such assurances. This can be compared to the ethical and legal constraints faced by journalists, like the case of Branzburg v. Hayes, where journalists were not exempt from revealing sources when subpoenaed, but in the case of CPAs, their professional code of conduct typically prohibits them from disclosing confidential information without the client's consent or a legal mandate.
There are exceptions that allow CPAs to disclose information, such as responding to a valid subpoena or a legitimate request from a regulatory body like a state board of accountancy (option 4), in which case they may be compelled to divulge information to fulfill their legal obligations.