PQ is a chord of length 8 cm of a circle of radius 5 cm. The tangent at $P$ and $Q$ intersect at a point $T$. The length of $TP$ is _________

Question

$\begin{array}{1 1} (a)\;20\;cm\\ (b)\;\frac{20}{3}\;cm \\(c)\; 10\;cm \\(d)\; \frac{10}{3}\;cm \end{array}$