Which of the following is an example of a hypervisor?

A hypervisor is a type of software or firmware that creates and runs virtual machines (VMs). It allows multiple operating systems to share a single hardware host while maintaining isolation between them. Each of the options listed is indeed a hypervisor, showcasing the variety of platforms available for virtualization.

VMware ESXi is a bare-metal hypervisor, meaning it is installed directly on the hardware and manages the VMs without needing a conventional operating system. This type of hypervisor is known for its robust performance, security features, and scalability in enterprise environments.

Citrix XenServer is also a well-known hypervisor that focuses on server virtualization. It provides features like live migration of VMs and is integral in managing many virtualized workloads in cloud computing environments.

Microsoft Hyper-V is Microsoft’s virtualization technology that is integrated into Windows Server. Also a type of hypervisor, it supports both server and desktop virtualization, making it a versatile choice for various applications, particularly in environments that already utilize Windows infrastructure.

By recognizing that all the listed platforms provide hypervisor functionalities and support virtualization, the correct answer encompasses the full range of examples. Each option contributes to the broader understanding of virtualization technologies and their implementations in different contexts.