The correct answer is (d) easy to use
Best explanation: UNIX is a multitasking operating system i.e. a user can run multiple tasks concurrently. Similarly, it is a multiuser system because it permits working with multiple users on a single operating system. But a major disadvantage of UNIX lies in the fact that the richness provided by its commands requires a special type of commitment to understand the subject. i.e. the user must be well aware of commands he is using and the functions performed by them.
