The best key performance indicator (KPI) to measure the effectiveness of the security patching process is the percentage of patches installed successfully within the expected time frame. This KPI can help to evaluate how well the security patching process meets the predefined objectives and standards, and how timely the patches are applied to reduce the risk exposure. The percentage of patches installed by the security administration team, successfully during the first attempt, or without causing an unplanned system outage are other possible KPIs, but they are not as relevant as the percentage of patches installed successfully within the expected time frame. References = ISACA Certified in Risk and Information Systems Control (CRISC) Certification Exam Question and Answers, question 7; CRISC Review Manual, 6th Edition, page 202.

The primary reason for establishing various threshold levels for a set of key risk indicators (KRIs) is to take appropriate actions in a timely manner. KRIs are metrics that provide information on the level of exposure to a given risk or the effectiveness of the controls in place. Threshold levels are predefined values that indicate when the risk level is acceptable, tolerable, or unacceptable. By establishing various threshold levels for a set of KRIs, the enterprise can monitor the risk situation and trigger the necessary responses before the risk becomes too severe or costly to mitigate. The other options are not the primary reasons for establishing various threshold levels, although they may be secondary benefits or outcomes of doing so. References = Risk and Information Systems Control Study Manual, Chapter 5: Risk and Control Monitoring and Reporting, page
189.

Providing assurance on risk management processes is the activity that should only be performed by the third line of defense, because it is the role and responsibility of the independent and objective assurance function, such as internal audit or external audit, to evaluate and report on the effectiveness and efficiency of the risk management processes and controls. The third line of defense is the last layer of the three lines of defense model, which is a framework that defines the roles and responsibilities of different functions and levels within the organization for risk management and control. The first line of defense is the operational management and staff, who are responsible for identifying, assessing, and managing the risks and controls within their areas of responsibility. The second line of defense is the oversight and support functions, such as risk management, compliance, or legal, who are responsible for establishing and monitoring the risk policies, standards, and frameworks, and providing guidance and advice to the first line of defense. The third line of defense is the assurance function, who are responsible for providing independent and objective assurance on the adequacy and effectiveness of the risk management processes and controls, and reporting to the senior management and the board of directors. Operating controls for risk mitigation, testing the effectiveness and efficiency of internal controls, and recommending risk treatment options are all activities that can be performed by the first or second line of defense, but not by the third line of defense, as they are not part of the assurance function.
References = Risk and Information Systems Control Study Manual, Chapter 2, Section 2.4.1, page 59

Residual risk is the risk that remains after the implementation of controls. It is important for a risk practitioner to verify that the residual risk is within the acceptable levels defined by the enterprise's risk appetite and tolerance. This ensures that the controls are effective in reducing the risk exposure to an acceptable level and align with the enterprise's objectives and strategy. References = CRISC Review Manual 27th Edition, page
131. Most Asked CRISC Exam Questions and Answers.

The risk likelihood is the element of the risk register that should be updated to reflect the change of implementing encryption on all databases that host customer data. The risk likelihood is the probability or frequency of a risk event occurring, and it is one of the factors that determine the risk level and priority. By implementing encryption, the organization reduces the risk likelihood of unauthorized access, disclosure, or breach of the customer data, as encryption protects the data from being read or modified by anyone who does not have the decryption key. Therefore, the risk likelihood should be updated to reflect the lower probability of the risk event after applying the encryption control. The other options are not the elements that should be updated, as they are either not affected by or not related to the change of implementing encryption. The inherent risk is the level of risk before applying any controls or mitigation measures, and it does not change after implementing encryption. The risk appetite is the amount of risk that the organization is willing to accept in pursuit of its objectives, and it is not influenced by the change of implementing encryption. The risk tolerance is the acceptable variation between the risk thresholds and thebusiness objectives, and it is not determined by the change of implementing encryption. References = Risk Register: A Project Manager's Guide with Examples [2023] * Asana; Risk Assessment in Project Management | PMI; Risk Assessment Process: Definition, Steps, and Examples; Risk Assessment - an overview | ScienceDirect Topics