对于法律凭证问题尚未解决的电子文件、在技术环境变迁下难以维护真实性的电子文件必须实行双套归档。

With respect to the Standards relating to preservation of confidentiality, which of the following statements is least accurate Members and candidates must keep information about all former current, and prospective clients confidential unless :（）

A. the information concerns illegal activities on the part of the clients.

B. disclosure is required by firms' policies.

C. the clients permit disclosure of the information.