Which of the following is NOT a key component of VMware vSphere?

The option of Cloud Manager is not considered a key component of VMware vSphere. VMware vSphere primarily includes core components like ESXi, which is the hypervisor that runs virtual machines, vCenter Server, which provides centralized management for vSphere environments, and vSphere Client, the user interface used to manage vSphere.

Cloud Manager, while a tool related to VMware's cloud offerings, specifically refers to a framework used in managing cloud resources and does not constitute a central component of the vSphere suite itself.

Understanding the components of vSphere is crucial for managing virtualized environments, as they facilitate the deployment, operation, and management of virtual machines and their underlying infrastructure effectively.