Which of the following server types is an ideal candidate for virtualization?

The mail server is an ideal candidate for virtualization due to its ability to efficiently utilize resources and allow for easier management. Virtualization allows multiple virtual mail servers to run on a single physical machine, optimizing hardware usage and reducing costs. This setup can lead to improved scalability—when demand grows, additional virtual servers can be quickly deployed without the need for additional physical hardware. Furthermore, mail servers often handle distinct functions, such as spam filtering and storage, which can be separated into different virtual servers for enhanced performance and security.

In contrast, a hypervisor is a software layer that enables virtualization and isn't a server type itself. A terminal server, while it can also work well in a virtualized environment, primarily provides remote desktop services and might not embody all the benefits of virtualization as prominently as a mail server. An application firewall, on the other hand, is generally not meant for virtualization due to its specialized purpose of monitoring and filtering traffic; it often requires high security and performance that may not be achieved as effectively in a virtualized environment.