The correct answer is A. Verify the DNS server settings. This is because the DNS server is responsible for resolving domain names to IP addresses, which is necessary for accessing the internet or named network resources.If the DNS server settings areincorrect or the DNS server is down, the technician will not be able to access these resources even if they have a valid IP address and can ping the default gateway1.
1: CompTIA A+ Certification Exam: Core 2 Objectives, page 16, section 1.10.

The best way to resolve the issue is to move factory applications to external memory. This will free up some space on the phone's internal storage, which is required for updating the phone.To do this, you can follow these steps1:
* Insert a microSD card into your phone if you don't have one already.
* Go to Settings > Apps and tap on the app you want to move.
* Tap on Storage and then on Change.
* Select the SD card option and tap on Move.
You may need to repeat this process for multiple apps until you have enough space to update your phone.
Alternatively, you can also clear the cache and data of some apps, or uninstall the apps that you don't use frequently.You can find more information onhow to fix insufficient storage error on your phone in these articles234. I hope this helps.

The technician opens the Apple icon menu, selects Force Quit, selects the frozen application in the list, and clicks Force Quit. This is the most common method of force quitting a program in macOS. This can be done by clicking on the Apple icon in the top left of the screen, selecting Force Quit, selecting the frozen application in the list, and then clicking Force Quit. This will force the application to quit and the spinning round cursor will disappear.

The user should install and run Linux and the required application as a virtual machine installed under the Windows OS. This solution would allow for parallel execution of the Linux application and Windows applications2.
The MOST efficient solution that allows for parallel execution of the Linux application and Windows applications is to install and run Linux and the required application as a virtual machine installed under the Windows OS. This is because it allows you to run both Linux and Windows together without the need to keep the Linux portion confined to a VM window3.

A software firewall is a program that monitors and controls the incoming and outgoing network traffic on a computer or a server. A software firewall can help prevent unauthorized LAN devices from accessing stored files on a company file server by applying rules and policies that filter the network packets based on their source, destination, protocol, port, or content. A softwarefirewall can also block or allow specific applications or services from communicating with the network, and alert the administrator of any suspicious or malicious activity12.
A software firewall is a better option than the other choices because:
* Password complexity (B) is a good practice to protect the file server from unauthorized access, but it is not sufficient by itself. Password complexity refers to the use of strong passwords that are hard to guess or crack by attackers, and that are changed frequently and securely. Password complexity can prevent brute force attacks or credential theft,but it cannot stop network attacks that exploit vulnerabilities in the file server software or hardware, or that bypass the authentication process34.
* Antivirus application and anti-malware scans (D) are important tools to protect the file server from viruses and malware that can infect, damage, or encrypt the stored files. However, they are not effective in preventing unauthorized LAN devices from accessing the files in the first place. Antivirus and anti-malware tools can only detect and remove known threats, and they may not be able to stop zero-day attacks or advanced persistent threats that can evade or disable them. Moreover, antivirus and anti-malware tools cannot control the network traffic or the file server permissions, and they may not be compatible with all fileserver platforms or configurations56.
References:
1: What is a Firewall and How Does it Work? - Cisco1 2: How to Harden Your Windows Server - ServerMania2 3: Password Security: Complexity vs. Length - Norton7 4: Password Hardening: 5 Ways to Protect Your Passwords - Infosec 5: What is Antivirus Software and How Does it Work? - Kaspersky 6: What is Anti-Malware? - Malwarebytes