B Doubt from capacitors

Charge stored by a capacitor and teh voltage across it are two inseparable concepts. They exist together physically how mathematically things could be different then. Draw a diagram to show what you wish to propose.

 

Whenever analysing a simple linear circuit, see what it does to a resistor. Here, think of connecting a resistor across 2 black boxes, one of them has a charged capacitor, and the other one has a capacitor in series with a voltage source. Now you connect the switch on them both at the same time.
This is akin to a step current response. If you would get the same step current response on both the black boxes, both these black boxes would behave the same way for all conditions.