$\Delta OAB$ is isosceles with $OA=OB$ and $AB$ is parallel to $CD$ and the height of the $\Delta OCD$ is $3$. The area of the $\Delta OAB$ is

Question

$\begin{array}{1 1} (a)\;12 \\ (b)\; 24 \\ (c)\; 26 \\ (d)\;30\end{array}$