
Take $\mathrm{O}$ to be the centre of the circle of radius $\mathrm{R}$ and angle $\mathrm{CAB}=60^{\circ}$
Figure:$Image$ 
$(A)$ the charge on the upper plate of $C _1$ is $2 CV _0$
$(B)$ the charge on the upper plate of $C _1$ is $CV _0$
$(C)$ the charge on the upper plate of $C _2$ is $0$
$(D)$ the charge on the upper plate of $C _2$ is $- CV _0$


