In an audit of financial statements in accordance with generally accepted auditing standards, an auditor is required to:

A$.$ Document the auditor's understanding of the entity's system of internal control.

B$.$ Search for significant deficiencies in the operation of controls.

C$.$ Perform tests of controls to evaluate the effectiveness of the entity's information system relevant to financial reporting.

D$.$ Determine whether controls operated effectively to prevent or detect material misstatements.