O is the centre of the circle with radius 5 cm $OP \perp CD, OQ \perp CD , AB \parallel CD, AB= 6 \;cm$ and $CD= 8 \;cm$. Hence PQ is _________

Question

$\begin{array}{1 1} 7\;cm \\ 9\;cm \\10\;cm \\14\;cm \end{array}$