An adverse opinion is issued when the auditor concludes that the financial statements materially depart from accounting standards and are not fairly presented. This is the most severe form of audit opinion, indicating significant misstatements.

• Option B (Qualified opinion): Incorrect because a qualified opinion is issued when there are specific exceptions or limitations, but the financial statements are otherwise fairly presented. The exceptions are detailed in the audit report.

• Option C (Disclaimer of opinion): Incorrect because a disclaimer is issued when the auditor is unable to form an opinion due to significant scope limitations or other constraints.