A ball is dropped, from a height of 20 m , 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 the instant when the ball is 12.8 m above the surface, the fish would observe the speed of the ball as
(1) 9 ms-1
(2) 12 ms-1
(3) 16 ms-1
(4) 21.33 ms-1