Which of the following best describes a graphical user interface (GUI)?

A graphical user interface (GUI) is best described as a visual interface that allows user interaction through graphics. This type of interface uses elements like windows, icons, buttons, and menus, making it easier for users to navigate and operate software applications without needing to memorize text-based commands. The GUI is designed to be intuitive, enabling users to interact with the system visually, enhancing accessibility and usability, particularly for those who may not be familiar with programming or command-line interfaces.

In contrast, the other options focus on different types of interfaces. A text-based command input system refers to command-line interfaces that require specific text commands, which do not provide the visual elements found in a GUI. The backend functionality of an operating system relates to processes that users typically do not interact with directly, whereas GUIs focus on the front-end user experience. Finally, an interface primarily used for programming would point toward development environments or code editors rather than the broad, user-friendly characteristics of a GUI designed for general use.