Figure given below shows two identical parallel plate capacitors connected to a battery with switch \[S\]closed. The switch is now opened and the free space between the plate of capacitors is filled with a dielectric of dielectric constant 3. What will be the ratio of total electrostatic energy stored in both capacitors before and after the introduction of the dielectric [IIT 1983]

• A.                    3 : 1
• B.                    5 : 1
• C.                    3 : 5
• D.                    5 : 3