A $20 \mu F$ capacitor and $40 \; \mu F$ capacitor are connected in series across $400\; V$ supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together. No external voltage is applied. What is potential difference across each capacitor .

Question

$(A)\;\large\frac{1600}{9} \\ (B)\;\large\frac{800}{9} \\ (C)\; 400 \\ (D)\;800$