Under Which of the Following Sets of Circumstances Might an Auditor

Under which of the following sets of circumstances might an auditor disclaim an opinion?

A) There are significant uncertainties affecting the financial report.
B) There has been a material change between periods in the method of the application of accounting principles.
C) The principal auditor decides to make reference to the report of another auditor who disclaimed an opinion on the audit of a subsidiary.The subsidiary contributed 6 per cent of operating revenue and profit but very little in other aspects.
D) The financial report contains a departure from generally accepted accounting principles, the effect of which is material.