Final answer:
An unmodified opinion in auditing is provided by the external auditor when they determine that the financial statements are presented fairly in all material respects, indicating a true and fair view of the company's financial state. An unmodified opinion is expressed by B) The external auditor when the auditor concludes the financial statements are presented fairly, in all material respects.
Step-by-step explanation:
An unmodified opinion is expressed by B) The external auditor when the auditor concludes the financial statements are presented fairly, in all material respects. This type of opinion, also known as an unqualified opinion, is the best type of report an entity can receive from an external auditor and indicates that the financial statements give a true and fair view of the company's financial position and the results of its operations. It is important to note that the word 'fairly' implies that any identified misstatements are deemed not material. The term 'in all material respects' underscores the practical limits of an audit, acknowledging that an audit is based on sampling and cannot guarantee that all potential errors have been identified or corrected.