When a Previously Expressed Opinion Is Updated from Qualified to Unmodified

When a previously expressed opinion is updated from qualified to unmodified, the auditors' report on comparative financial statements should

A) not modify the previously expressed opinion or refer to factors affecting the opinion on the prior years' financial statements.
B) update the opinion expressed on the prior years' financial statements but provide no explanation for the updated opinion.
C) not modify the previously expressed opinion but include a reference to the footnote describing the factors affecting the opinion on the prior years' financial statements.
D) update the previously expressed opinion and explain the reasons for the change, including a reference to the footnote describing the change.