$\Delta ABC \cong \Delta PQR$. Area of $\Delta PQR = 24 \;sq.cm$. Then the length of $AD =$ <br>

Question

$\begin{array}{1 1} (a)\; 12 \; cm \\ (b) \; 8\; cm \\(c)\; 6\; cm \\ (d)\; 4\;cm \end{array}$