The first step for the risk practitioner to address the situation of extended network outages that have exceeded tolerance is to recommend a root cause analysis of the incidents. A root cause analysis is a process of identifying and resolving the underlying causes of a problem or an event. By performing a root cause analysis, the risk practitioner can determine why the network outages occurred, what factors contributed to them, and how they can be prevented or reduced in the future. Recommending additional controls, updating the risk tolerance level, and updating the incident-related risk trend are possible steps that may follow the root cause analysis, but they are not the first step. References = ISACA Certified in Risk and Information Systems Control (CRISC) Certification Exam Question and Answers, question 4; CRISC Review Manual, 6th Edition, page 153.

A source code review is the process of examining and analyzing the source code of an application to identify any vulnerabilities, errors, or flaws that may compromise the security, functionality, or performance of the application. A source code review is the most effective way to identify an application backdoor prior to implementation, as it can detect any hidden or unauthorized code that may allow unauthorized access, bypass security controls, or execute malicious commands. A source code review can also help to improve the quality and reliability of the application, and ensure compliance with the coding standards and best practices. References = CRISC Review Manual, 7th Edition, page 181.

* A vendor risk assessment is a process of evaluating and managing the risks associated with outsourcing IT services or functions to a third-party provider, such as a cloud service provider.
* One of the most important documents to request from a cloud service provider during a vendor risk assessment is an independent audit report. This is a report that provides an objective and reliable assurance on the quality, security, and performance of the cloud service provider's operations, processes, and controls, based on the standards and criteria established by an independent auditor or a recognized authority, such as ISACA, ISO, NIST, etc.
* An independent audit report helps to verify the compliance and effectiveness of the cloud service provider's risk management practices, identify any gaps or issues that may affect the service delivery or security, and recommend improvements or corrective actions.
* The other options are not the most important documents to request from a cloud service provider during a vendor risk assessment. They are either secondary or not essential for vendor risk management.
The references for this answer are:
* Risk IT Framework, page 22
* Information Technology & Security, page 16
* Risk Scenarios Starter Pack, page 14

Policies and standards are important components of the risk management process, as they define the objectives, expectations, and requirements for managing risk within the organization. Policies and standards are also the means by which senior management formally approves and communicates the risk practices to the stakeholders, ensuring that the risk management process is aligned with the organizational strategy, culture, and values. Policies and standards also provide the authority and accountability for the risk management roles and responsibilities, as well as the criteria and metrics for measuring and reporting risk performance.

The business owner is the person who is responsible for approval when a change in an application system is ready for release to production. The business owner is the person who has the authority and accountability for the business process or function that is supported by the application system. The business owner should approve the change to ensure that it meets the business requirements, objectives, and expectations, and that it does not introduce any adverse impacts or risks to the business operations. The information security officer, the IT risk manager, and the chief risk officer (CRO) are not responsible for the approval of the change, although they may provide input, feedback, or oversight. References = Risk and Information Systems Control Study Manual, Chapter 3, Section 3.4.1, page 3-32.