If p, q, r are all real numbers, then (p q)3 + (q r)3 + (r p)3 isequal to

If p, q, r are all real numbers, then (p q)3 + (q r)3 + (r p)3 i

1.	If p, q, r are all real numbers, then (p q)3 + (q r)3 + (r p)3 isequal to
A.	(p q) (q r) (r p)
B.	3(p q) (q r) (r p)
C.	0
D.	1
Answer» C. 0