Q. Two train P and Q are running in the same direction on parallel track such that P is faster than Q. If packets of equal weights are exchanged between them , then
(a) P will be accelerated but Q will be retarded
(b) P will be retarded but Q will be accelerated
​(c) There will be no change in velocity   of P, but Q will be retarded
(d) There will be no change   in velocity of P, but Q will be accelerated