Which of the following statements about engagement letter is NOT appropriate?
选项：

A:An engagement letter provides a oral agreement of the terms of the audit engagement between the auditor and management or those charged with governance.;
B:An engagement letter confirms a common understanding of the terms of the audit engagement and helps to avoid misunderstandings with respect to the audit.;
C:Management's responsibilities should be stated in the engagement letter.;
D:Auditor's responsibilities should be stated in the engagement letter.