An open water tight railway wagon of mass `5xx10^(3)` kg coasts at initial velocity of `1.2 m//s` without friction on a railway track. Rain falls vertically downwards into the wagon. What change then occurred in the kinetic energy of the wagon, when it has collected `10^(3)` kg of water
A. `10m//s`
B. `3m//s`
C. `0.2m//s`
D. `9m//s`
