Toolbars can be added to a Windows 10 machine by right-clicking the __________ and then pointing to Toolbars.

The correct answer is the Taskbar. In Windows 10, the Taskbar serves as both a location for running applications and a hub for various utility features, including toolbars. By right-clicking on the Taskbar, users can access a context menu that includes the option to point to Toolbars. This allows users to add additional functionality through toolbars, which can contain shortcuts to various applications, folders, or web resources.

The other options don't provide access to the same functionality. For instance, the Desktop primarily serves as the main working area where icons and shortcuts are arranged, while the Start menu is focused on application launching and accessing system features. The Control Panel is a place for system settings and configurations but does not have options for modifying the Taskbar directly or adding toolbars. Thus, the Taskbar is uniquely suited for adding toolbars in the Windows 10 environment.