Correct choice is (c) UNIX was not written in ‘C’ language
Easy explanation: One of the most attractive features of UNIX is that it supports multi-user and multitasking environment which makes it so popular among its users. There are many UNIX variants available in the market. Solaris Unix, AIX, HP Unix, BSD are some of the examples. Linux is also a flavor of UNIX which is freely available. Unix was developed in 1969 by AT&T employees Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna at Bell Labs and was written in ‘C’.