(c) $I = \frac{R}{R_{2} + r}$ (since finally no current flows through capacitor) ∴ Potential difference across $R_{2},V = IR_{2} = \frac{ER_{2}}{R_{2} + r}$ ∴ Charge on the capacitor $\mathcal{Q =}CV = \frac{CER_{2}}{R_{2} + r}$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.