Which of the following is a primary function of a network operating system?

A primary function of a network operating system (NOS) is network resource sharing. This capability allows multiple users and devices within a network to access and share resources such as files, printers, and other devices seamlessly. An effective NOS manages the permissions and access rights for these resources, ensuring that the resources are utilized efficiently while maintaining security and control over who can access what within the network.

In contrast, the other options focus on different aspects of computing and networking. Virtual machine management, while important, typically falls under the realm of hypervisors or virtualization software rather than the core functions of a network operating system. Website hosting is generally associated with web servers and the infrastructure needed to deliver web content, rather than the operating system that manages network resources. File recovery deals with data restoration processes and is more related to data management and backup solutions, thus not directly aligned with the primary functions of a network operating system.