In the adjoining figure P and Q are points on the sides $AB$ and $AC$ respectively of $\Delta ABC$ such that $AP = 3.5 \;cm, PB = 7\;cm, AQ = 3 \;cm, QC = 6\; cm$ and $PQ = 4.5\; cm$. The measure of $BC$ is equal to

Question

$\begin{array}{1 1} 13.5\;cm\\ 15\;cm \\ 12.5 \;cm\\ 9\;cm \end{array} $