What is the value of $tan^{-1} \bigg(cos^{-1}\large\frac{8}{17}\bigg)$ ?

Question

$\begin{array}{1 1} \large\frac{6}{7} \\\large\frac{15}{8} \\\large\frac{16}{7} \\ \large\frac{6}{27} \end{array}$