The key goal of the containment stage in an incident response process is to limit further damage from occurring. This involves taking immediate steps to isolate the affected systems or network segments to prevent the spread of the incident and mitigate its impact. Containment strategies can be short-term, to quickly stop the incident, or long-term, to prepare for the eradication and recovery phases.

A Memorandum of Understanding (MOU) is a formal agreement that outlines the roles and responsibilities of each party involved in a particular process or project, especially within security frameworks. In the context of cybersecurity, an MOU is commonly used to clarify and document the security responsibilities of different departments or entities involved. It helps ensure everyone understands their specific duties and contributions to security, which is crucial for coordination and risk management. According to CompTIA Security+ guidelines, while options A, C, and D describe other forms of agreements, they do not capture the essential purpose of an MOU as accurately as option B does.

Penetration testing is the best strategy to evaluate the security of the software without the source code.
Penetration testing is a type of security testing that simulates real-world attacks on the software to identify and exploit its vulnerabilities. Penetration testing can be performed on the software as a black box, meaning that the tester does not need to have access to the source code or the internal structure of the software. Penetration testing can help the analyst to assess the security posture of the software, the potential impact of the vulnerabilities, and the effectiveness of the existing security controls12. Static testing, vulnerability testing, and dynamic testing are other types of security testing, but they usually require access to the source code or the internal structure of the software. Static testing is the analysis of the software code or design without executing it. Vulnerability testing is the identification and evaluation of the software weaknesses or flaws.
Dynamic testing is the analysis of the software code or design while executing it345. References: Penetration Testing - OWASP, What is a Penetration Test and How Does It Work?, Static Code Analysis | OWASP Foundation, Vulnerability Scanning Best Practices, Dynamic Testing - OWASP

The correct answer is A because SLOs - service-level objectives are measurable targets used to evaluate whether a service or process is meeting expected performance levels. When incident response is outsourced to a third party, SLOs help the organization measure whether the provider is meeting key performance expectations, such as detection time, response time, remediation time, and reporting quality.
Exact supporting extract: the Secbay CySA+ guide defines SLOs as specific, measurable targets set for the performance and reliability of a service or process. It also states that SLOs provide a framework for defining and measuring effectiveness, and that reporting on SLOs allows stakeholders to assess performance and make informed decisions.
The same guide explains that SLOs depict explicit measurements and may be set by a company or defined as part of a service-level agreement with a service provider. It also states that estimating whether SLOs are being met is a typical component of SLA management.
The official CySA+ objectives include SLOs under metrics and KPIs for reporting and communication.
Why the other options are incorrect:
B is incorrect because SLOs are performance targets, not a method for identifying hidden costs.
C is incorrect because SLOs may support risk management, but they do not directly calculate an objective risk score.
D is incorrect because risk appetite is a governance/risk-management concept, not the purpose of SLOs.
A is correct because SLOs allow the organization to measure third-party IR performance against defined KPIs.

Vulnerability 2 should be prioritized as it is exploitable, has high exploit activity, and is exposed externally according to the SMITTEN metric. References: Vulnerability Management Metrics: 5 Metrics to Start Measuring in Your Program, Section: Vulnerability Severity.