Final answer:
Auditors may modify their opinion on internal control if they find significant control deficiencies, material misstatements, or evidence of fraud during their audit that suggest the internal controls are not effective.
Step-by-step explanation:
An example of a scenario which would cause the auditors to modify the opinion on internal control would be if there were control deficiencies identified during the audit that are significant enough to deem the internal controls over financial reporting as not effective.
Auditors perform tests to assess the effectiveness of internal controls. Should they encounter issues such as material misstatements in the financial statements that were not prevented or detected on a timely basis, or evidence of fraud or noncompliance with laws and regulations that could have a material effect on the financial statements, they might conclude that the internal control has deficiencies. In such cases, the auditors would not give an unqualified opinion but rather an adverse opinion or a disclaimer of opinion, depending on the circumstances.