Choice "C" is correct. A CPA is required to disclosed confidential client information if the information is subpoenaed and relevant to a court case. The IRS would have to do more than request the information in a letter. The IRS would have to subpoena the information and show that the information was relevant to an examination (audit).
Choice "a" is incorrect because a CPA is required to reveal confidential client information to a state CPA society voluntary quality control review panel when requested.
Choice "d" is incorrect because a CPA is required to reveal confidential information in an official investigation of the AICPA/state trial board.
Choice "b" is incorrect because a CPA is required to reveal confidential client information if it is subpoenaed and relevant to a court case.
