In the given  $R–C$  circuit switch S is closed at t = 0 and the variation of potential drop across the resistor $\left(V_R\right)$ and across capacitor $\left(V_C\right)$ is represented by given plots, then 

$$\begin{gathered} q=C\epsilon (1-e^{-t/\tau }) \\ \tau =CR \\ i=\frac{\epsilon }{R}{e}^{-t/\tau } \\ {v}_R=iR=\epsilon e^{-t/\tau } \\ {v}_C=\frac{q}{c}=\epsilon (1-e^{-t/\tau }) \end{gathered}$$

Now for  $V_0\Rightarrow V_R=V_C$
$\Rightarrow e^{-t/\tau }=\frac{1}{2}\Rightarrow V_0=V_R=V_C=\frac{\epsilon }{2}\Rightarrow \epsilon =2V_0$
for  $V_1+V_2+V_1=2V_0$  
Hence  $A\&C$ are correct options