A is incorrect as internal auditors are not required to be members of any professional body. C is incorrect as external auditors report to shareholders rather than those charged with governance. D is incorrect as internal auditors can be independent of the company, if, for example, the internal audit function has been outsourced.
Where there is a significant change in ownership of the company, ISA 210 Agreeing the Terms of Audit Engagements recommends that a new audit engagement letter is sent to avoid misunderstandings.