Choice "C" is correct. In evaluating the reasonableness of an accounting estimate, the auditor should first obtain an understanding of how management developed its estimate.
Choice "b" is incorrect. After first obtaining an understanding of how management developed its estimate, the auditor should use one or a combination of the following approaches: a) review and test the process used by management to develop the estimate, b) develop an independent expectation of the estimate to corroborate the reasonableness of management's estimate, or c) review subsequent events.
Choice "d" is incorrect. After having first obtained an understanding of how management developed its estimate, the auditor should consider testing management's process by assessing the appropriateness of the key factors or assumptions used in preparing the estimate.
Choice "a" is incorrect. After first obtaining an understanding of how management developed its estimate, the auditor should use one or a combination of the following approaches: a) review and test the process used by management to develop the estimate, b) develop an independent expectation of the estimate to corroborate the reasonableness of management's estimate, or c) review subsequent events.