Tangent and normal are drawn at $P(16, 16)$ on the parabola $y^2 =16x$, which intersect the axis of the parabola at A and B, respectively. If $C$ is the centre of the circle through the points $P, \;A$ and $B$ and $\angle CPB=\theta$, then a value of $\tan \theta$ is :

Question

( A ) $2$
( B ) $3$
( C ) $\frac{4}{3}$
( D ) $\frac{1}{2}$