Which of the Following Situations Would Require Auditors to Add

Which of the following situations would require auditors to add an explanatory paragraph to their report on comparative financial statements?

A) An unqualified opinion is issued in the current year while a qualified opinion was issued in prior years.
B) A qualified opinion is issued in the current year because of a scope limitation; because this limitation was not encountered in prior years, the opinion issued in those years was unqualified.
C) The updated opinion issued on prior years' financial statements differs from the opinion originally issued on those financial statements.
D) The auditors' unqualified opinion issued on prior years' financial statements is still considered to be appropriate.