Which of the following best defines a virtual machine (VM)?

A virtual machine (VM) is best defined as an emulation of a computer system that operates like a physical computer. This definition captures the essence of virtualization technology, where multiple virtual instances run on a single physical host. A VM functions independently with its own operating system and applications, simulating the same environment as a physical machine would. This enables users to run different operating systems and manage resources more efficiently, providing the flexibility and scalability that modern data centers require.

The other options represent different concepts in computing. A physical server, while essential for hosting VMs, does not describe the function or nature of a VM itself. Network storage solutions pertain to data storage rather than the virtualization of computing resources. Lastly, a hardware component describes physical parts of a computer system rather than the software-defined nature of VMs. Thus, the definition provided in the correct answer accurately reflects the distinct characteristics of virtual machines.