Mapping the risk scenarios by likelihood and impact on a chart is the best method of comparing risk scenarios, as it helps to visualize and prioritize the different types and levels of risks associated with each option. A chart can also facilitate the communication and decision-making process by showing the trade-offs and benefits of each option. A chart can be based on qualitative or quantitative data, depending on the availability and accuracy of the information.
References = CISM Review Manual 2022, page 371; CISM Exam Content Outline, Domain 1, Task 1.32; A risk assessment model for selecting cloud service providers; Security best practices for IaaS workloads in Azure

Mitigate is the risk treatment option that has been applied by implementing a firewall in front of the legacy application because it helps to reduce the impact or probability of a risk. Mitigate is a process of taking actions to lessen the negative effects of a risk, such as implementing security controls, policies, or procedures.
A firewall is a security device that monitors and filters the network traffic between the legacy application and the external network, blocking or allowing packets based on predefined rules. A firewall helps to mitigate the risk of unauthorized access, exploitation, or attack on the legacy application that cannot be patched.
Therefore, mitigate is the correct answer.
References:
https://simplicable.com/risk/risk-treatment
https://resources.infosecinstitute.com/topic/risk-treatment-options-planning-prevention/
https://www.enisa.europa.eu/topics/risk-management/current-risk/risk-management-inventory/rm-process/risk- treatment.

The best automated control to resolve the issue of security incidents not being appropriately escalated by the help desk is to integrate incident response workflow into the help desk ticketing system. This will ensure that the help desk staff follow the predefined steps and procedures for handling and escalating security incidents, based on the severity, impact, and urgency of each incident. The incident response workflow will also provide clear guidance on who to notify, when to notify, and how to notify the relevant stakeholders and authorities.
This will improve the efficiency, effectiveness, and consistency of the incident response process.
References = CISM Review Manual, 16th Edition, page 2901; A Practical Approach to Incident Management Escalation2