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. update the previously expressed opinion and explain the reasons for the change, including a reference to the footnote describing the change.

• d. 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.