A particle is projected with a velocity u making an angle $\mathrm{\theta }$ with the horizontal. At any instant, its velocity V is at right angles to its initial velocity u ; then V is

• A

  u cos $\mathrm{\theta }$

• B

  u tan $\mathrm{\theta }$

• C

  u cot $\mathrm{\theta }$

• D

  u sec $\mathrm{\theta }$