Two chords of a circle $\overline{PQ}$ and $\overline{RS}$ intersect at a point $O$, where $RO = PO + 5, PQ = 8, So = 10$. <br> Find the length of PO. <br>

Question

$\begin{array}{1 1} (a)\; 10 \\ (b)\; 8 \\ (c)\; 16 \\ (d)\; 20 \end{array}$