two level cpu scheduling

Question

36. Consider the following justifications for commonly using the two-level CPU scheduling :
I. It is used when memory is too small to hold all the ready processes.
II. Because its performance is same as that of the FIFO.
III. Because it facilitates putting some set of processes into memory and a choice is
made from that.
IV. Because it does not allow to adjust the set of in-core processes.
Which of the following is true ?
(A) I, III and IV (B) I and II
(C) III and IV (D) I and III

Answer 1

option D is correct ans.

https://en.wikipedia.org/wiki/Two-level_scheduling.

this shows that the process is not following any order that is (FIFO)

and it adjust wiyh memory and processor