The most useful information to determine mitigating controls when a core data center went offline abruptly for several hours affecting many transactions across multiple locations is the root cause analysis. Root cause analysis is a technique that identifies the underlying factors or reasons that caused the problem or incident.
Root cause analysis can help to understand the nature, scope, and impact of the problem or incident, and to prevent or reduce the recurrence or severity of the problem or incident in the future. Root cause analysis can also help to identify and prioritize the appropriate mitigating controls that address the root causes of the problem or incident. The other options are not as useful as root cause analysis, as they are related to the investigation, evaluation, or measurement of the problem or incident, not the resolution or prevention of the problem or incident. References = Risk and Information Systems Control Study Manual, Chapter 4: Risk and Control Monitoring and Reporting, Section 4.4: Key Control Indicators, page 211.

* A compliance-based CSA focuses on ensuring that the business unit follows the policies and procedures established by the enterprise, regardless of the actual risk level or impact of the controls.
* A risk-based CSA focuses on identifying and evaluating the risks that may affect the business unit's objectives, and designing and implementing controls that are appropriate to mitigate those risks.
* A compliance-based CSA may not capture all the high-risk issues that exist in a business unit, especially if they are not aligned with the enterprise's standards or expectations.
* A risk-based CSA may identify more high-risk issues than a compliance-based CSA, because it considers both internal and external factors that may affect the business unit's performance or security.
* Therefore, a difference in results between a previous control self-assessment (CSA) and an audit indicates that either one of them was not risk-based, but rather compliance-based.
The references for this answer are:
* Risk IT Framework, page 9
* Information Technology & Security, page 3
* Risk Scenarios Starter Pack, page 1

Section: Volume D

Section: Volume D

is incorrect. The scenario does not describe risk acceptance, Acceptance is a strategy
that provides for formal acknowledgement of the existence of a risk and the monitoring of that risk.