(A) A
(B) X
(C) S
(D) Z
The answer is: (B) X
SOLUTION
There are 6 people: A, P, R, X, S and Z:
(1)___(2)___(3)___(4)___(5)___(6)
S and Z are in the center:
(1)___(2)___(S)___(Z)___(5)___(6)
A and P are at the ends.
(P)___(2)___(S)___(Z)___(5)___(A)
R is sitting to the left of A:
(P)___(2)___(S)___(Z)___(R)___(A)
Finally,
(P)___(X)___(S)___(Z)___(R)___(A)
Note that R is sitting left to A. So, A was at the right-end while P was at the left-end.