The normal to the curve $x=a(\cos \theta+\theta \sin \theta), y=$
$a(\sin \theta-\theta \cos \theta)$ at any point $\theta$ is such that $\quad$ [2005]
(A) It passes through the origin
(B) It makes angle $\frac{\pi}{2}+\theta$ with the $x$-axis
(C) It passes through $\left(a \frac{\pi}{2},-a\right)$
(D) It is at a constant distance from the origin