The IT Auditing Approach Referred to as "Auditing Through the System

The IT auditing approach referred to as "Auditing through the system" is necessary under which of the following conditions?

A) Supporting documents are available in both electronic and paper form.
B) The auditor does not require evaluation of computer controls.
C) The auditor wants to test computer controls as a basis for evaluating risk and reducing the amount of substantive audit testing required.
D) The use of the IT system has a low impact on the conduct of the audit.