A key control indicator (KCI) is a metric that provides information on the extent to which a given control is meeting its intended objectives in terms of loss prevention, reduction, etc. A KCI should have an explicit relationship to both the specific control and the specific risk against which the control has been implemented.
For risk related to IT infrastructure failure, a possible control is to have a recovery plan that can restore the critical IT services and minimize the impact of the failure. A KCI that can measure the effectiveness of this control is the number of successful recovery plan tests, which indicates how well the recovery plan can be executed in a real scenario. The higher the number of successful tests, the lower the risk of IT infrastructure failure. Therefore, this is the best KCI among the given options. References = Integrating KRIs and KPIs for Effective Technology Risk Management Key Control Indicator (KCI) - CIO Wiki Infrastructure Issues: Understanding and Mitigating Risks

An independent review is typically sought to provide an objective assessment of the IT risk management program, ensuring that it aligns with the organization's overall strategy and objectives. The reviewer can identify areas where the program may not be effectively addressing the organization's strategic goals or where improvements can be made to better manage IT risks.

Reviewing configuration settings is the best way for an organization to ensure that servers are compliant to security policy, because it helps to check and verify that the servers are configured and maintained according to the established security standards and guidelines, and that any deviations or violations are identified and corrected. A configuration setting is a parameter or option that defines the behavior or functionality of a server, such as a system, an application, or a service. A security policy is a document that outlines the security objectives, principles, and rules that the organization and its employees must follow, and the consequences of non-compliance. Reviewing configuration settings is the best way, as it helps to ensure that the servers are secure and compliant, and that any security risks or issues are detected and resolved. Reviewing change logs, server access logs, and anti-malware compliance are all possible ways to ensure that servers are compliant to security policy, but they are not the best way, as they do not provide a comprehensive and consistent view of the configuration settings and their compliance status. References = Risk and Information Systems Control Study Manual, Chapter 5, Section 5.3.2, page 200

According to the CRISC Review Manual (Digital Version), key risk indicator (KRI) thresholds are the most likely elements of a risk register to change as a result of change in management's risk appetite, as they reflect the acceptable levels of risk exposure for the organization. KRIthresholds are the values or ranges that trigger an alert or a response when the actual KRI values deviate from the expected or desired values. KRI thresholds help to:
Monitor and measure the current risk levels and performance of the IT assets and processes Identify and report any risk issues or incidents that may require attention or action Evaluate the effectiveness and efficiency of the risk response actions and controls Align the risk management activities and decisions with the organization's risk appetite and risk tolerance If the management's risk appetite changes, the KRI thresholds may need to be adjusted accordingly to ensure that the risk register reflects the current risk preferences and expectations of the organization.
References = CRISC Review Manual (Digital Version), Chapter 4: IT Risk Monitoring and Reporting, Section 4.1: IT Risk Monitoring, pp. 217-2181