A projectile is fired with a speed  u at an angle $\theta$ with the horizontal. Its speed when its direction of motion makes an angle $\text{'}\alpha \text{'}$ with the horizontal is

• A

  $u\sec \text{θ}\cos \alpha$

• B

  $u\sec \text{θ}\sin \alpha$

• C

  $u\cos \text{θ}\sec \alpha$

• D

  $u\sin \text{θ}\sec \alpha$