Keychain is a feature of macOS that securely stores passwords, account numbers, and other confidential information for your Mac, apps, servers, and websites1. You can use the Keychain Access app on your Mac to view and manage your keychains and the items stored in them1. Keychain can also sync your passwords and other secure information across your devices using iCloud Keychain1. Keychain can be used as a password manager in macOS to help you keep track of and protect your passwords.
References: 1: Manage passwords using keychains on Mac (https://support.apple.com/guide/mac-help/use- keychains-to-store-passwords-mchlf375f392/mac)

Low-level wiping is the best data destruction method for recycling old hard drives for reuse. Low-level wiping is a process that overwrites every bit of data on a hard drive with zeros or random patterns, making it impossible to recover any data from the drive. Low-level wiping also restores the drive to its factory state, removing any bad sectors or errors that may have accumulated over time. Low-level wiping can be done using specialized software tools or hardware devices that connect to the drive. Degaussing, standard formatting, and deleting are not suitable data destruction methods for recycling old hard drives for reuse. Degaussing is a process that exposes a hard drive to a strong magnetic field, destroying both the data and the drive itself.
Degaussing renders the drive unusable for reuse. Standard formatting is a process that erases the data on a hard drive by removing the file system structure, but it does not overwrite the data itself. Standard formatting leaves some data recoverable using forensic tools or software utilities. Deleting is a process that removes the data from a hard drive by marking it as free space, but it does not erase or overwrite the data itself. Deleting leaves most data recoverable using undelete tools or software utilities. References:
Official CompTIA learning resources CompTIA A+ Core 1 and Core 2, page 15 CompTIA A+ Complete Study Guide: Core 1 Exam 220-1101 and Core 2 Exam ..., page 105

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

The scenario described in the question suggests that the workstation has been infected by a ransomware, which is a type of malware that encrypts the files on the target system and demands a ransom for the decryption key12. The file extension .enc is commonly used by some ransomware variants to mark the encrypted files34.
The developer is unable to open the database files manually because they are encrypted and require the decryption key, which is usually held by the attacker.
The best option for recovering the data is to utilize the backups, assuming that the backups are recent, valid, and not affected by the ransomware. Backups are copies of the data that are stored in a separate location or device, and can be used to restore the data in case of a disaster, such as a ransomware attack . By restoring the data from the backups, the developer can avoid paying the ransom and losing the data permanently.
Accessing a restore point is not a good option, because restore points are snapshots of the system settings and configuration, not the data files. Restore points can help to undo some system changes, such as installing a faulty driver or software, but they cannot recover the encrypted data files .
Rebooting into safe mode is also not a good option, because safe mode is a diagnostic mode that allows the system to run with minimal drivers and services, but it does not affect the data files. Safe mode can help to troubleshoot some system issues, such as malware infections, but it cannot decrypt the data files .
Using an AV to scan the affected files is also not a good option, because an AV is a software that can detect and remove some malware, but it cannot decrypt the data files. An AV can help to prevent or remove some ransomware infections, but it cannot recover the encrypted data files .
References1: CompTIA A+ Certification Exam Core 2 Objectives, page 10 2: CompTIA A+ Core 2 (220-1102) Complete Video Course, Lesson 26 Documentation 3: How to remove .enc file virus (Ransomware virus removal guide) 4: Enc File Extension - What is an .enc file and how do I open it? : CompTIA A+ Certification Exam Core 2 Objectives, page 13 : CompTIA A+ Core 2 (220-1102) Complete Video Course, Lesson 26 Documentation : What is a restore point? : How to use System Restore on Windows 10 : [What is Safe Mode?] : [How to boot into Safe Mode on Windows 10] : CompTIA A+ Certification Exam Core 2 Objectives, page 10 : [Can antivirus software remove ransomware?]

The most effective clarifying question for the help desk technician to ask the user in order to understand the issue is A. What is the error message? This question will help the technician to identify the possible cause and solution of the problem, as the error message will provide specific information about the nature and location of the error, such as the server name, the port number, the protocol, the authentication method, or the network status. The error message will also help the technician to troubleshoot the issue by following the suggested steps or searching for the error code online.
This question is more effective than the other choices because:
B: Does the program work on another computer? is not a very helpful question, as it will not reveal the source of the error or how to fix it. The program may work on another computer for various reasons, such as different network settings, firewall rules, permissions, or software versions. However, this question will not tell the technician what is wrong with the user's computer or the remote server, or what needs to be changed or updated to make the program work.
C: Did the program ever work? is not a very relevant question, as it will not address the current issue or how to resolve it. The program may have worked in the past, but it may have stopped working due to changes in the network configuration, the server status, the software updates, or the user credentials.
However, this question will not tell the technician what has changed or how to restore the program functionality.
D: Is anyone else having this issue? is not a very useful question, as it will not explain the reason or the solution for the error. The issue may affect only the user, or multiple users, depending on the scope and the impact of the error. However, this question will not tell the technician what is causing the error or how to fix it for the user or the others.
References:
How to Troubleshoot Terminal Emulation Problems - Techwalla : How to Read and Understand Windows Error Messages - Lifewire : How to Troubleshoot Network Connectivity Problems - How-To Geek : How to Troubleshoot Software Problems - dummies : How to Troubleshoot Common PC Issues For Users - MakeUseOf