Automated data indicating that risk has been reduced provides the most tenable evidence that a business process control is effective, because it shows the actual impact and outcome of the control on the risk level. A demonstration that the control is operating as designed, a successful walk-through of the associated risk assessment, and a management attestation that the control is operating effectively are not the most tenable evidence, because they are based on subjective judgments, assumptions, or expectations, not on objective facts or results. References = CRISC: Certified in Risk & Information Systems Control Sample Questions