P, Q, R, S, T, U and V are sitting on a wall in a straight row, and all of them are facing north. R is on the immediate right of S. Q is at one of the extreme end and has T as his immediate neighbour. V is the immediate neighbour of T and U. S is sitting third from the extreme right end. Which of the following pairs is sitting at each of the extreme end ?
AQR
BQS
CQU
DPQ