The answer to this question may depend on several factors, such as the number and type of Windows VMs, the number and type of host machines, the number and type of users, and the specific licensing terms and conditions of each licensing model. However, based on the information available from the web search results, one possible answer is per user.
Per user licensing model is a licensing model that allows a user to access Windows VMs from any device, regardless of the number of devices or VMs. Per user licensing model is available for Windows 10 Enterprise E3/E5, Windows VDA E3/E5, and Microsoft 365 F3/E3/E5. Per user licensing model may offer the greatest number of concurrent Windows VMs to run on a host for the lowest cost if the following conditions are met:
* The user needs to access multiple Windows VMs from different devices, such as desktops, laptops, tablets, or smartphones.
* The user needs to access Windows VMs that run different versions or editions of Windows, such as Windows 10 Enterprise, Windows 10 Pro, or Windows 7 Enterprise.
* The user needs to access Windows VMs that run on different types of host machines, such as physical servers, virtual servers, or cloud servers.
* The user does not need to access Windows VMs that run on dedicated hardware or have specific performance or security requirements.
According to the web search results 1, per user licensing model costs $84 per user per year for Windows 10 Enterprise E3, $168 per user per year for Windows 10 Enterprise E5, $100.80 per user per year for Windows VDA E3, and $196.80 per user per year for Windows VDA E5. These prices are based on the Open License Program and may vary depending on the volume and agreement level2 Per core licensing model is a licensing model that requires a license for each core of the processor on the host machine that runs Windows VMs. Per core licensing model is available for Windows Server 2022 Datacenter and Standard editions. Per core licensing model may offer a lower cost than per user licensing model if the following conditions are met:
* The host machine has a low number of cores or a high core density.
* The host machine runs a high number of Windows VMs with low resource consumption.
* The host machine runs only Windows Server VMs with the same edition as the host machine.
According to the web search results 2, per core licensing model costs $6,155 for 16 core licenses for Windows Server 2022 Datacenter edition and $1,069 for 16 core licenses for Windows Server 2022 Standard edition.
These prices are suggested retail prices and may vary depending on the reseller2 Per instance licensing model is a licensing model that requires a license for each instance of Windows that runs on a host machine or a VM. Per instance licensing model is available for Windows Server 2022 Essentials edition and some older versions of Windows Server. Per instance licensing model may offer a lower cost than per user or per core licensing model if the following conditions are met:
* The host machine runs only one instance of Windows Server with low resource consumption.
* The host machine does not need to run any other VMs or applications.
* The host machine does not need any advanced features or functions that are available in Datacenter or Standard editions.
According to the web search results 2, per instance licensing model costs $501 for one server license for Windows Server 2022 Essentials edition. This price is suggested retail price and may vary depending on the reseller2 Per concurrent user licensing model is a licensing model that allows a certain number of users to access Windows VMs at the same time, regardless of the number of devices or VMs. Per concurrent user licensing model is not available for any current version of Windows or Windows Server. Per concurrent user licensing model was available for some older versions of Windows Server Terminal Services or Remote Desktop Services, but it was discontinued due to complexity and compliance issues. Therefore, per concurrent user licensing model cannot be used for running Windows VMs on a host.

https://serverfault.com/questions/490261/cannot-use-any-yum-command-no-space-left-on-device

Explanation
To disable root login over SSH, the server administrator needs to edit the SSH configuration file located at
/etc/ssh/sshd_config. This file contains various settings for the SSH daemon that runs on the server and accepts incoming SSH connections. The administrator needs to find the line that says PermitRootLogin and change it to no or comment it out with a # symbol. Then, the administrator needs to restart the SSH service for the changes to take effect. References:
https://www.howtogeek.com/828538/how-and-why-to-disable-root-login-over-ssh-on-linux/

Explanation
Encryption at rest is a type of encryption methodology that would most likely be used to ensure encrypted data cannot be retrieved if a device is stolen. Encryption at rest is a process of encrypting stored data on a device such as a hard drive, SSD, USB flash drive, or mobile device. This way, if the device is lost or stolen, the data cannot be accessed without the encryption key or password. Encryption at rest can be implemented using software tools such as BitLocker on Windows or FileVault on Mac OS, or hardware features such as self-encrypting drives or Trusted Platform Module chips. End-to-end encryption is a type of encryption methodology that ensures encrypted data cannot be intercepted or modified by third parties during transmission over a network. Encryption in transit is a type of encryption methodology that protects encrypted data while it is moving from one location to another over a network. Public key encryption is a type of encryption algorithm that uses a pair of keys: a public key that can be shared with anyone and a private key that is kept secret by the owner. References:
https://www.howtogeek.com/196541/bitlocker-101-what-it-is-how-it-works-and-how-to-use-it/
https://www.howtogeek.com/443611/how-to-encrypt-your-macs-system-drive-removable-devices-and-individua
https://www.howtogeek.com/428483/what-is-end-to-end-encryption-and-why-does-it-matter/https://www.howto