(a) List the FOUR main elements of a computer. (b) What are multiprogramming and multithreading? (c) List Two advantages of user level threads (ULTs) over kernel level threads (KLTs). (d) List TWO disadvantages of ULTs compared with KLTs. (e) An engineer designs an automatic fire sprinkler system using a computer for detecting fire accidents in two rooms. If any sprinkler of the two rooms sprinkles water, the fire alarm will sound. For each room, the engineer uses one thread to check each sprinkler if water is sprinkling or not. The major duty of the system is to respond to any fire accident in these two rooms. Suggest if two user level threads (ULTs) are used or two kernel level threads (KLTs) are used. Give a sensible reason to support your decision