Windows 10
The correct answer is D. Unattended installation. An unattended installation is a way of installing Windows 10 without requiring any user input or interaction. It uses a configuration file called answer file that contains the settings and preferences for the installation, such as the product key, language, partition, and network settings.
An unattended installation can be performed by using a bootable USB flash drive or DVD that contains the Windows 10 installation files and the answer file1. This is the fastest way for the technician to install Windows 10 on a newly built computer, as it automates the whole process and saves time.
A factory reset is a way of restoring a computer to its original state by deleting all the data and applications and reinstalling the operating system. A factory reset can be performed by using the recovery partition or media that came with the computer, or by using the Reset this PC option in Windows 10 settings2. A factory reset is not a way of installing Windows 10 on a newly built computer, as it requires an existing operating system to be present.
A system restore is a way of undoing changes to a computer's system files and settings by using a restore point that was created earlier. A system restore can be performed by using the System Restore option in Windows
10 settings or by using the Advanced Startup Options menu3. A system restore is not a way of installing Windows 10 on a newly built computer, as it requires an existing operating system and restore points to be present.
An in-place upgrade is a way of upgrading an existing operating system to a newer version without losing any data or applications. An in-place upgrade can be performed by using the Windows 10 Media Creation Tool or by running the Setup.exe file from the Windows 10 installation media. An in-place upgrade is not a way of installing Windows 10 on a newly built computer, as it requires an existing operating system to be present.

This would ensure that the support documentation reflects the current state of the network and prevents any confusion or mismatch during a network outage. Updating the network diagrams is also one of the best practices for network documentation, as stated in the Official CompTIA A+ Core 2 Study Guide1. The other options are not as effective or feasible as option B. Performing annual network topology reviews is too infrequent and may not capture recent changes. Allowing network changes once per year is too restrictive and may not meet the business needs. Routinely backing up switch configuration files is important, but it does not help with identifying new switches or devices on the network.

Explanation
After implementing a change authorized by the change advisory board (CAB), the technician should document the date and time of change as part of the post-implementation review. This helps to track the change history, verify the success of the change, and identify any issues or incidents caused by the change1. Documenting the purpose of the change, the risk level, and the findings of the sandbox test are all part of the pre-implementation activities that should be done before submitting the change request to the CAB2.
References: 2:
https://www.manageengine.com/products/service-desk/itil-change-management/cab-change-advisory-board.html
1:
https://www.servicenow.com/content/dam/servicenow-assets/public/en-us/doc-type/success/quick-answer/chang