The most likely solution to this issue is to enable cellular data. After a business trip, the user may have disabled cellular data to avoid roaming charges, or the phone may have been set to Wi-Fi only for internet access. Enabling cellular data would restore internet access outside of Wi-Fi networks.
Reference: CompTIA A+ 220-1101 Exam Objectives, Domain 1.4 Mobile Devices - Wireless/Cellular Network

The user can change the wallpaper using a Windows 10 Settings tool by following these steps12:
* Open Settings by pressing the Windows key and typing Settings, or by clicking the gear icon in the Start menu.
* Select Personalization from the left navigation menu.
* On the right side of the window, click Background.
* In the Background settings, click the drop-down menu and select Picture as the background type.
* Click Browse and then locate and open the image the user wants to use as the wallpaper.
The other options are incorrect because they do not lead to the Background settings or they do not allow the user to browse for an image. Accounts, System, and Apps are not related to personalization settings. Your info, Display, and Apps & features are not related to wallpaper settings.
References: 1: https://support.microsoft.com/en-us/windows/change-your-desktop-background-image-
175618be-4cf1-c159-2785-ec2238b433a8 2: https://www.computerhope.com/issues/ch000592.htm

BitLocker is only available on Windows 10 Pro, Enterprise, and Education editions1. Therefore, the technician is unable to find the BitLocker Drive Encryption menu item in Control Panel because it is not included in the Windows 10 Home edition1.

On macOS, uninstalling an application typically involves locating the app in Finder and dragging it to the Trash. This method is straightforward and commonly used for removing unwanted applications. The other options do not directly relate to the standard process of uninstalling applications on a Mac.

educating the user on the solution that was performed is a good next step after resolving an issue. This can help prevent similar issues from happening again and empower users to solve problems on their own.