What is a Virtual Machine (VM)?

A Virtual Machine (VM) is best defined as a software emulation of a physical computer that runs an operating system and applications. This allows the VM to function just like a physical machine, enabling users to run multiple operating systems on a single physical server. Each VM operates in its own environment, with its own virtual hardware, which includes a virtual CPU, RAM, hard drives, and network interfaces, effectively simulating an entire physical computing system.

The ability of VMs to operate independently is a key benefit, as it enables better resource management, flexibility, and scalability within IT infrastructures. Multiple VMs can share the underlying physical resources while being isolated from each other, thereby enhancing security and performance.

The other choices describe concepts that do not correctly define a VM. For example, a physical server running multiple applications does not encapsulate the concept of virtualization; it focuses on physical hardware rather than software emulation. A tool for monitoring server performance relates to system management and analysis, which is distinct from the functionality of a virtual machine. An anti-virus program for servers specifically deals with security threats and does not pertain to the virtualization topic. Thus, the correct identification of a VM as a software emulation helps clarify its role and significance in computing environments.