Explanation
Think and work holistically
No service, practice, process, department, or supplier stands alone. The outputs that the organization delivers to itself, its customers, and other stakeholders will suffer unless it works in an integrated way to handle its activities as a whole, rather than as separate parts.
https://www.bmc.com/blogs/itil-guiding-principles/#:~:text=5.,rather%20than%20as%20separate%20parts.

A service request is a formal request from a user for something to be provided. Service requests are typically less complex and are either approved or denied based on the budget, need, or urgency.
An emergency change to apply a security patch (A) is not a service request because it is an urgent change that needs to be made to address a security vulnerability. The implementation of a workaround (B) is not a service request because it is a temporary solution to a problem. Managing an interruption to a service (D) is not a service request because it is an incident that needs to be resolved.
Providing a virtual server for a development team (C) is a service request because it is a request for a new service that can be fulfilled by the IT department.

Reference: https://www.knowledgehut.com/tutorials/itil4-tutorial/it-service-management-concepts

Explanation
Emergency changes. These are changes that must be implemented as soon as possible; for example, to resolve an incident or implement a security patch. Emergency changes are not typically included in a change schedule, and the process for assessment and authorization is expedited to ensure they can be implemented quickly. As far as possible, emergency changes should be subject to the same testing, assessment, and authorization as normal changes, but it may be acceptable to defer some documentation until after the change has been implemented, and sometimes it will be necessary to implement the change with less testing due to time constraints. There may also be a separate change authority for emergency changes, typically including a small number of senior managers who understand the business risks involved."
https://itsm.tools/why-what-change-management/#:~:text=Emergency%20changes.&text=Emergency%20change