The ratio of the speed of a projectile at the point of projection to the speed at the top of its trajectory is x. The angle of projection with the horizontal is

• A

  ${\sin }^{-1} x$

• B

  ${\cos }^{-1} x$

• C

  ${\sin }^{-1} (1/x)$

• D

  ${\cos }^{-1} (1/x)$