An auditor's primary duty is to verify the accuracy of financial statements and ensure that they present a true and fair view of the organization's financial condition. Duties include:
Measuring business events and communicating their impact (A).
Verifying the balance sheet and ensuring it represents a true and fair financial position (B).
Reporting whether the profit and loss account represents a true and fair view (D).
However, preparing final accounts or computing taxable income (C) falls under the role of an accountant, not an auditor.