Explanation
https://support.microsoft.com/en-us/windows/common-file-name-extensions-in-windows-da4a4430-8e76-89c5-5
.pkg and .dmg are files used to distribute and install applications on macOS. .pkg files are installer packages that may contain multiple files and executable code, while .dmg files are disk images that can contain a single bundled application or multiple applications. .app files are typically the main executable files for macOS applications. The other options listed are file extensions for applications or installers on other platforms (such as .deb for Debian-based Linux systems, .msi for Windows, and .apk for Android). This information is covered in the Comptia A+ Core2 documents/guide under the Mac OS section.

Explanation
The account access level the user will need to access advanced features and configuration settings for several applications while adhering to corporate policy requiring a least privilege environment is a standard account. This is because a standard account allows the user to access advanced features and configuration settings for several applications while adhering to corporate policy requiring a least privilege environment1.

Explanation
If a rootkit has caused a deep infection, then the only way to remove the rootkit is to reinstall the operating system. This is because rootkits are designed to be difficult to detect and remove, and they can hide in the operating system's kernel, making it difficult to remove them without reinstalling the operating system
https://www.minitool.com/backup-tips/how-to-get-rid-of-rootkit-windows-10.html

Explanation
When a user experiences unexpected or erratic behavior while browsing the internet, it could be caused by the DNS servers. DNS translates human-readable domain names (like google.com) into IP addresses, which computers can use to communicate with web servers. If the DNS servers are not functioning correctly or have been compromised, it can result in the browser being redirected to unintended websites.