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.

Explanation
The most likely cause of this issue is that a router was misconfigured and was blocking traffic. This would explain why remote users who were not connected to corporate resources did not have any issues.

Changing the network channel is the best solution to minimize the issue of employees and patients not being the only people on the Wi-Fi network5 References: 3. Sample CompTIA Security+ exam questions and answers. Retrieved from
https://www.techtarget.com/searchsecurity/quiz/Sample-CompTIA-Security-exam-questions-and-answers

Task Manager is the best tool to use to disable applications on startup in Windows 10. Task Manager is a built-in utility that shows the current processes, performance, and users on a system. It also has a Startup tab that lists the applications that run on boot and their impact on the system. The technician can use Task Manager to disable or enable any application on startup by right-clicking on it and selecting the appropriate option. System Configuration, Performance Monitor, and Group Policy Editor are other tools that can be used to manage system settings, but they are not as simple or convenient as Task Manager for this task. References:
Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 13 CompTIA A+ Complete Study Guide: Core 1 Exam 220-1101 and Core 2 Exam ..., page 103

The 32-bit operating system can only run 32-bit applications, so the technician should execute the 32-bit installer. The "x86" in the file name refers to the 32-bit architecture.
https://www.digitaltrends.com/computing/32-bit-vs-64-bit-operating-systems/