If p, q denote the lengths of the perpendiculars from the origin on the lines $x\sec \alpha -y\cos ec\alpha =a$ and $x\cos \alpha +y\sin \alpha =a\cos 2\alpha$ then

• A

  $4p^2+q^2=a^2$

• B

  $p^2+q^2=a^2$

• C

  $p^2+2q^2=a^2$

• D

  $4p^2+q^2=2a^2$