A ball is thrown vertically downwards from a height of 20m with an initial velocity 𝒗_𝒐. It collides

A ball is thrown vertically downwards from a height of 20m with an initial velocity 𝒗_𝒐. It collides with ground, loses 50 percent of its energy in collision and rebounds to the same height. The initial velocity 𝒗_𝒐 is (Take g=𝟏𝟎〖𝒎𝒔〗^(−𝟐))a)10m/s b)14m/s c)20m/s d)28m/s