The operating systems designed for smartphones include iOS and Android. iOS is developed by Apple Inc.
for its iPhone range, while Android, developed by Google, is used across a variety of devices from different manufacturers. Both operating systems are specifically tailored to provide a mobile computing experience, with interfaces, applications, and functionalities designed for touchscreen input and mobile hardware.

VNC (Virtual Network Computing) is a protocol that allows a technician to simultaneously view and control a user's screen remotely. VNC uses a server-client model, where the user's computer runs a VNC server and the technician's computer runs a VNC client. VNC can work across different platforms and operating systems3. SSH (Secure Shell) is a protocol that allows a technician to access a user's command-line interface remotely, but not their graphical user interface. VPN (Virtual Private Network) is a technology that creates a secure and encrypted connection over a public network, but does not allow screen sharing. RDP (Remote Desktop Protocol) is a protocol that allows a technician to access a user's desktop remotely, but not simultaneously with the user.

To enable contactless payment, NFC (Near Field Communication) (Option C) needs to be enabled. NFC is the technology used in most mobile payment systems to enable close-range communication between the phone and a payment terminal.
* Wi-Fi (Option A) and Bluetooth (Option D) are unrelated to contactless payments.
* Nearby share (Option B) is a file-sharing feature, not a payment technology.
CompTIA A+ Core 2 References:
* 2.7 - Explain common mobile device security settings, including enabling NFC for mobile payments.

Smart card and password is an example of two-factor authentication (2FA), not multi-factor authentication (MFA). MFA requires two or more authentication factors. Smart card and password is an example of two-factor authentication (2FA)2

Quarantining the infected system is the most appropriate way to remediate the issue of an infection that the antivirus software cannot remove. Quarantining means isolating the system from the network and other devices to prevent the infection from spreading or causing further damage. Quarantining also allows the technician to perform further analysis and removal of the infection without risking the security of other systems or data.
Some of the steps involved in quarantining an infected system are:
Disconnect the system from the internet and any local network connections, such as Wi-Fi, Ethernet, Bluetooth, or USB.
Disable any file-sharing or remote access services on the system, such as Windows File Sharing, Remote Desktop, or TeamViewer.
Use a separate device to download and update the antivirus software and any other tools that may be needed to remove the infection, such as malware scanners, rootkit removers, or bootable rescue disks.
Transfer the updated antivirus software and tools to the infected system using a removable media, such as a CD, DVD, or USB flash drive. Scan the removable media for any infections before and after using it on the infected system.
Run the antivirus software and tools on the infected system and follow the instructions to delete or quarantine the infection. If the infection is persistent or complex, it may require booting the system from a rescue disk or using a Linux live disc to access and clean the system files.
After the infection is removed, restore the system to a previous clean state using System Restore, backup, or recovery partition. Scan the system again to ensure that it is clean and secure. Reconnect the system to the network and update the system and the antivirus software.
References:
How to Identify and Repair Malware or Virus Infected Computers, section 31 Uninstalling Antivirus Software, the Clean Way: 40 Removal Tools & Instructions, section 22 How to manually remove an infected file from a Windows computer3 The Official CompTIA A+ Core 2 Study Guide (220-1102), page 2194