Which of the following statements about the appropriateness of an audit strategy ismost correct? There are two answers. I need more explanation about why they are correct or wrong.

A.Assuming effective controls, a predominately substantive approach is likely to be the most efficient approach when auditing a large client.

B.Assuming effective controls, a predominately controls approach is likely to be the most efficient audit approach to reduce audit risk for the assertion of occurrence for sales revenue when there are a large number of repetitive sales transactions.

C.Inherent risk for an assertion for a balance is assessed as high. The auditor assesses control risk as high and does not perform test of controls. The auditor performs extensive substantive tests of transactions and balances in response to a desired low level of detection risk.

D.Inherent risk about an assertion for a balance is assessed as low. The auditor assesses control risk as low and performs extensive tests of controls to support this assessment. Detection risk is assessed as high and the auditor does not perform any substantive procedures.