Answer:
(b) Windows is an open source operating system (<em>This is not correct</em>)
Explanation:
Option a is <em>correct</em> because Xerox PARC(Palo Alto Research Center), which is a subsidiary of the Xerox corporation, has been greatly responsible for invention and development in modern computing devices. Some of these developments are in Ethernet and graphical user interface (making use of menus, icons e.t.c).
Option b is <em>not correct</em> because Windows Operating system is not an open source operating system. Open source OS means users can interact with the driving code of the OS and make modifications. Windows does not support this feature. Operating systems that are open source include Linux and OpenSolaris.
Option c is <em>correct</em>. An operating system has two main components - the kernel and the user interface. The core component of an operating system is the Kernel as it interacts directly with the hardware and manages system resources. The user interface on the other hand allows users to interact with the kernel of the operating system using texts and/or graphics as commands.
Option d is <em>correct</em>. Linux operating system is an open source OS. Therefore, the source code is made available to the public for examination and modification.
