Risk threshold is the maximum amount of risk that an organization is willing to accept for a given activity or decision. It is also known as risk appetite or risk tolerance. Risk threshold helps an organization to prioritize and allocate resources for risk management. Risk indicator, risk level, and risk score are different ways of measuring or expressing the likelihood and impact of a risk, but they do not describe the maximum allowance of accepted risk. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, page
34; Accepting Risk: Definition, How It Works, and Alternatives

The best answer is C. WAF.
XSS (Cross-Site Scripting) is a web application attack that injects malicious scripts into web content. A WAF (Web Application Firewall) is specifically designed to inspect, filter, and block malicious HTTP and HTTPS traffic targeting web applications. It can help detect and prevent common attacks such as XSS, SQL injection, and other application-layer threats.
Why the other options are incorrect:
A). NGFWA next-generation firewall provides advanced network security features, but it is not as specifically focused on web application attacks as a WAF.
B). UTMUnified Threat Management combines multiple security features in one platform, but it is not the best answer for preventing a web application attack like XSS.
D). NACNetwork Access Control focuses on controlling which devices can connect to the network. It does not directly prevent XSS.
From the SY0-701 perspective, attacks against web applications are best mitigated by controls specifically designed for application-layer inspection, making WAF the correct answer.

A tabletop exercise is a simulated scenario that tests the effectiveness of a security incident response plan. It involves gathering the relevant stakeholders and walking through the steps of the plan, identifying any gaps or issues that need to be addressed. A tabletop exercise is a good way to validate the documentation created by the security manager and ensure that the team is prepared for various types of security incidents.
References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 6: Risk Management, page 2841. CompTIA Security+ Certification Kit: Exam SY0-701, 7th Edition, Chapter 6: Risk Management, page 2842.