A combination of capacitors is set up as shown in the figure. The magnitude of the electric field due to a point charge Q (having a charge equal to the sum of the charges on the $4 \mu F$ and $9 \mu F$ capacitors), at a point distant $30\; m$ from it, would equal :

Question

$\begin{array}{1 1} (1) 240 \;N/C \\(2) 360\;N/C \\ (3)420\;N/C \\ (4)480\;N/C \end{array}$