Solution:GNU is an extensive collection of free software, which can be used as an operating system or can be used in parts with other operating systems. GNU stands for "GNU's Not Unix," chosen because GNU's design is Unix-like, but differs from Unix by being free software and containing no Unix code.
Development of the GNU operating system was initiated by Richard Stallman while he worked at MIT Artificial Intelligence Laboratory. Richard Stallman made the initial announcement of the GNU Project in September, 1983. The GNU operating system is upward-compatible with Unix. Hence, statement of option (d) is not true.