The correct answer is option 'A', Windows Logo.

Explanation:
The Windows Logo key, also known as the Start key, is a key on the keyboard of a Windows-based computer. It is usually located on the bottom row, between the Ctrl and Alt keys, and is marked with the Windows logo.

The Windows Logo key is an important key that is used to access various functions and features in the operating system. One of its primary functions is to display or hide the Start menu, which is a central hub for accessing programs, files, and settings on a Windows computer.

When the Windows Logo key is pressed, it activates the Start menu, which appears on the left side of the screen. The Start menu provides quick access to commonly used programs, recently opened files, and various system settings. It also allows users to search for specific files or programs using the search bar at the bottom.

Pressing the Windows Logo key again while the Start menu is open will hide the Start menu and return the user to the desktop or the previously active window.

In addition to displaying or hiding the Start menu, the Windows Logo key has several other functions. Some of these functions include:

- Opening the Windows Explorer: Pressing Windows Logo key + E opens the Windows Explorer, which is a file management tool that allows users to browse and manage files and folders on their computer.

- Opening the Action Center: Pressing Windows Logo key + A opens the Action Center, which is a central hub for managing notifications, system settings, and other system-related tasks.

- Opening the Settings app: Pressing Windows Logo key + I opens the Settings app, which allows users to customize various aspects of their computer, such as display settings, network settings, and privacy settings.

- Opening the Task View: Pressing Windows Logo key + Tab opens the Task View, which displays all open windows and allows users to switch between them or create virtual desktops.

Overall, the Windows Logo key is a versatile key that provides quick access to various functions and features in the Windows operating system, including the ability to display or hide the Start menu.