A boy throws a ball with a velocity u at an angle $\mathbf{\theta }$ with the horizontal. At the same instant, he starts running with uniform velocity to catch the ball before it hits the ground. To achieve this, he should run with a velocity of

• A

  u cos $\mathbf{\theta }$

• B

  u sin $\mathbf{\theta }$

• C

  u tan $\mathbf{\theta }$

• D

  u sec $\mathbf{\theta }$