When auditing financial statements of a private company, the minimum work an auditor must perform in connection with a company's internal control is best described by which of the following statements?

a Determine whether the company's control policies are designed well enough to prevent material misstatements.

b Perform exhaustive tests of accounting controls and evaluate the company's control system effectiveness.

c Design procedures to search for significant deficiencies in the actual operation of the company's internal control.

d Prepare auditing working papers that document the auditor's understanding of the company's internal control.