The Correct Answer of this question is C) KDE
Qt pronounced "cute" is a free and open-source widget toolkit for making graphical user interfaces as well as cross-platform applications that run on several software and hardware platforms like Linux, Windows, macOS, Android or embedded systems with little or no alter in the underlying codebase while yet being a native application with native capabilities and speed. Qt is presently being developed by The Qt Company, a publicly listed company, and the Qt Project beneath open-source governance, involving particular developers and organizations performing to advance Qt. Qt is available under both commercial licenses and open source GPL 2.0, GPL 3.0, and LGPL 3.0 licenses.
For Further Reading Go To This link https://en.wikipedia.org/wiki/Qt_(software)