Two capacitors `C_(1)=3muF` and `C_(2)=6muF` in series, are connected in parallel to a third capacitor `C_(3)=4muF`. This arrangement is then connected to a battery of e.m.f., =`30V`, as shown. The energy lost by the battery in charging the capacitors
A. `900muJ`
B. `1800muJ`
C. `2700muJ`
D. `3600muJ`