Which of the following BEST describes a virtual machine?

A host is the physical server on which the hypervisor and virtual machines run, not the virtual machine itself.

VDI (Virtual Desktop Infrastructure) is a technology that hosts desktop environments on a central server, and while it uses virtual machines, VDI itself is not the definition of a virtual machine.

Hyper-V is a specific hypervisor product from Microsoft, which is the software that creates and runs virtual machines, not the virtual machine itself.

In virtualization terminology, a virtual machine (VM) is referred to as a 'guest' operating system because it runs on top of the hypervisor, which itself runs on a 'host' physical server. The guest OS operates as if it has direct access to the hardware but is actually abstracted by the hypervisor.