There are 20 books of which 4 are single volumes and the other are books of 8, 5 and 3 volumes respectively. In how many ways can all these books be arranged on a self so that volumes of the same book are not separated ?

There are 20 books of which 4 are single volumes and the other are boo

1.	There are 20 books of which 4 are single volumes and the other are books of 8, 5 and 3 volumes respectively. In how many ways can all these books be arranged on a self so that volumes of the same book are not separated ?
A.	7! 8! 5! 3!
B.	7! 8! 4! 3!
C.	7! 6! 5! 3!
D.	None of these
Answer» B. 7! 8! 4! 3!