An Auditor May Be Asked to Report on the Client's

An auditor may be asked to report on the client's internal control structure. Which one of the following is NOT a reason why the auditor would be asked to prepare this?

A) It is required by contractual obligation on the client.
B) It is required by regulatory obligation on the client.
C) It is required by statutory obligation on the client.
D) It is part of the financial report audit.