A particle is projected with a velocity u making an angle $\mathrm{\theta }$ with the horizontal. At any instant its velocity becomes v which is perpendicular to the initial velocity u. Then v is

• A

  $\mathrm{u} \cos \mathrm{\theta }$

• B

  u tan $\theta$

• C

  u $\sec \mathrm{\theta }$

• D

  u $\cot \mathrm{\theta }$