The two plates $x$ and $y$ of a parallel plate capacitor of capacitance $C$ are given a charge of amount $Q$ each. $x$ is now joined to the positive terminal and $y$ to the negative terminal of a cell of emf $V=\frac{Q}{C}$, then select the correct statements 

The total charge on the plate $x$ will be $2Q$

The energy supplied by the cell is $C{V}^2$

The total charge on the plate $y$ will be zero

A charge of amount $Q$ will flow from the posistive terminal to the negative terminal of the cell through the capacitor