The Primary Purpose of the Auditors' Study of Internal Control

The primary purpose of the auditors' study of internal control for a nonpublic entity is

A) to provide constructive suggestions to the client for improving its internal control.
B) to report on internal control as required by Auditing Standard No. 5.
C) to identify and detect fraud and irregularities perpetrated by client personnel.
D) to determine the nature, timing, and extent of further audit procedures.