Choice "D" is correct. An auditor would review the client's accounting policies and procedures as part of obtaining an understanding of the client's operations and business. This understanding is important because it affects the design of internal control, which in turn impacts planned auditing procedures.
Choice "c" is incorrect. Although the auditor might consider the client's accounting policies and procedures when designing a sampling plan, this is not the primary reason for the auditor's review of the client's policies and procedures.
Choice "a" is incorrect. The client's accounting policies and procedures would not affect preliminary judgments about materiality, which are generally based on either annualized interim financial statements or annual financial statements from a prior period.
Choice "b" is incorrect. The client's accounting policies and procedures would not affect the nature of reports to be rendered. The nature of reports to be rendered would be based on the type of engagement and the specific results of that engagement.