
Therefore, potential at $\mathrm{A}$ is :
$V_{a}=4+V_{b}$
$V_{a}=4+2=6 V$
Therefore, charge on $4 \mu F$ capacitor is given by :
$q=C \times\left(V_{a}-V_{b}\right)$
$q=4 \times(6-6)$
$q=0 \mu C$
Therefore, option (A) is correct.
[Given: In SI units $\frac{1}{4 \pi \epsilon_0}=9 \times 10^9, \ln 2=0.7$. Ignore the area pierced by the wire.]