Choice "C" is correct. Inquiry of the predecessor auditor is a required pre-acceptance procedure. However, consent of the prospective client must be obtained before a CPA can make such inquiries of the predecessor auditor.
Choice "b" is incorrect. Obtaining an understanding of the client's industry and business is a planning procedure performed after an engagement is accepted.
Choice "d" is incorrect. A management representation letter is not obtained until the end of the audit.
Choice "a" is incorrect. Obtaining a preliminary understanding of the client's control environment is an audit procedure (required by the second standard of fieldwork) that would be performed after an engagement is accepted.