Multifactor authentication (MFA) significantly enhances security by requiring two or more forms of verification before granting access to an account or system. This method is highly effective against brute-force attacks, where attackers attempt to guess a user's password through repeated trials. By implementing MFA, even if a password is compromised, unauthorized access is still prevented without the additional authentication factor(s), such as a code from a smartphone app, a fingerprint, or a physical security token.
Multifactor authentication: Provides an additional layer of security beyond just the password, making it much harder for attackers to gain unauthorized access through brute-force methods, as they would need to compromise more than one authentication factor.
Encryption (B) is crucial for protecting data at rest and in transit, but it does not directly prevent brute-force login attempts. Increased password complexity (C) can deter brute-force attacks by making passwords harder to guess, but it is not as effective as MFA in preventing access when passwords are compromised. A secure password vault (D) helps users manage and store their passwords securely, which can indirectly contribute to security by allowing users to keep more complex passwords, but it does not directly prevent brute-force attacks on accounts.

The best way to address the security and privacy concerns caused by a malware infection on a smartphone is to uninstall all recently installed applications and schedule an antivirus scan. Uninstalling the applications that may have introduced the malware can help remove the source of infection and prevent further damage.
Scheduling an antivirus scan can help detect and remove any remaining traces of malware and restore the device's functionality.
References: CompTIA A+ Core 2 (220-1102) Certification Study Guide, Chapter 5: Mobile Devices, Section
5.3: Mobile Device Security1

The technician should quarantine the system first1
Reference:
CompTIA A+ Certification Exam: Core 2 Objectives Version 4.0. Retrieved from https://partners.comptia.org
/docs/default-source/resources/comptia-a-220-1102-exam-objectives-(3-0)

Removing the user-installed antivirus software program is the best way to resolve the issue of extremely slow performance caused by installing additional real-time protection antivirus software on a PC. Having more than one antivirus software program running at the same time can cause conflicts, resource consumption and performance degradation. Uninstalling one antivirus software program and installing a different one, activating real-time protection on both antivirus software programs, enabling the quarantine feature on both antivirus software programs and launching Windows Update are not effective ways to resolve the issue.
Verified References: https://www.comptia.org/blog/why-you-shouldnt-run-multiple-antivirus-programs-at-the- same-time https://www.comptia.org/certifications/a

A new employee will need to sign an AUP before being granted login access to the network. An AUP is an Acceptable Use Policy that defines the rules and guidelines for using network resources and services in an organization. An AUP typically covers topics such as security, privacy, ethics, compliance and liability issues related to network usage. An AUP helps protect the organization and its users from legal, regulatory and reputational risks associated with network activities. An MSDS is a Material Safety Data Sheet that provides information about hazardous substances and how to handle them safely. An MSDS is not related to network access or usage. A EULA is an End User License Agreement that specifies the terms and conditions for using a software product or service. A EULA is usually provided by software vendors or developers and does not apply to network access or usage in general. A UAC is a User Account Control that is a security feature that prompts users for permission or confirmation before performing certain actions that require elevated privileges or affect system settings. A UAC is not a document that needs to be signed by users but a mechanism that helps prevent unauthorized changes or malware infections on a system. References:
CompTIA A+ Core 2 (220-1002) Certification Exam Objectives Version 4.0, Domain 5.1