Answer:
D. reports involving other auditors.
Step-by-step explanation:
An auditor would issue an unmodified opinion audit report which contains modified wording (without adding an emphasis-of-matter paragraph) s/he should include reports involving other auditors.
Commonly, these audit reports rely upon a different CPA firm, thus the auditor can indicate that her/his responsibility is shared in the modified wording of an unmodified or unqualified report.