A ball is dropped from a height of `20m` above the surface of water in a lake. The refractive index of water is `4//3`. A fish inside the lake, in the line of fall of the ball, is looking at the ball. At an instant, when the ball is `12.8m` above the water surface, the fish sees the speed of ball as `(g=10m//sec^2)`

Options

A. `9ms^(-1)`
B. `12ms^(-1)`
C. `16ms^(-1)`
D. `21.33ms^(-1)`

Answer

C