State the audit opinion that is required in each of the following circumstances and levels of materiality:

(i) Circumstance: The auditor is unable to obtain sufficient appropriate evidence concerning sales and inventory levels.

Level of materiality: Material and pervasive.

(ii) Circumstance: The auditor and management disagree about the application of accounting policies.

Level of materiality: Material and pervasive.

(iii) Circumstance: The auditor and management disagree about a disclosure.

Level of materiality: Material but not pervasive

(iv) Circumstance: The auditor is unable to obtain sufficient appropriate evidence concerning the clients depreciation expense.

Level of materiality: Material but not pervasive.