The correct answer isDbecauseinternal control effectiveness measured through direct testingprovides the most valid basis for conducting risk assessments. Direct testing produces objective evidence about whether controls are designed appropriately and operating effectively. It is stronger and more reliable than estimates, external inference, or peer-based assumptions because it evaluates the actual control environment of the organization.

The other options are less valid:

A. Internal control effectiveness measured through inference from external assessmentmay provide useful insight, but it is indirect and may not reflect the organization’s actual internal control performance.

B. Control effectiveness determined through subject matter expertise estimationcan support assessment, but it remains judgment-based rather than evidence-based.

C. Inferences of internal control effectiveness from peer reportsare indirect and may not be relevant to the organization’s own environment, systems, or risk exposure.

Exact Extracts supporting the answer:

“To best identify information systems control deficiencies gap analysis is used. It highlights the discrepancies between desired control objectives and actual control design and operational effectiveness.”

“The MOST important criterion when reviewing information security controls is ensuring that the controls are effectively addressing risk.”

“The BEST way to ensure that an information systems control is appropriate and effective is to verify that the risk associated with the control is mitigated.”

“To determine control effectiveness it ' s essential to verify that the control meets the test results of intended objectives.”

“Testing the control to ensure that the risk has been adequately mitigated is the best action to take once a new control has been implemented validating that the control effectively addresses the identified risk.”

These extracts support that the most valid evidence of control effectiveness comes from actual verification and testing, not from assumptions or indirect sources. Therefore,direct testingprovides the strongest validity for risk assessments.

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