If the parabolas $Y^2= 4x$ and $x^2=32y$ intersect at $(16,8)$ at an angle $\theta$ then $\theta$ is equal to

Question

$\begin{array}{1 1}(A)\;\tan^{-1} (\frac{3}{5}) \\(B)\;\tan^{-1} (\frac{4}{5}) \\(C)\;\pi \\(D)\;\frac{\pi}{2} \end{array}$