In multi-programmed systems, it is advantageous if some programs such as editors and compilers can be shared by several users. Which of the following must be true of multi-programmed systems in order that a single copy of a program can be shared by several users?

In multi-programmed systems, it is advantageous if some programs such

1.	In multi-programmed systems, it is advantageous if some programs such as editors and compilers can be shared by several users. Which of the following must be true of multi-programmed systems in order that a single copy of a program can be shared by several users?
A.	I only
B.	II only
C.	Ill only
D.	I, II and III
Answer» D.