Complete combustion of $1.80 \mathrm{g}$ of an oxygen containing compound $\left({\mathrm{C}}_{\mathrm{x}}{\mathrm{H}}_{\mathrm{y}}{\mathrm{O}}_{\mathrm{z}}\right)$ gave $2.64 \mathrm{g}$ of ${\mathrm{CO}}_2$ and $1.08 \mathrm{g}$ of ${\mathrm{H}}_2\mathrm{O}.$ The percentage of oxygen in the organic compound is :

Using the provided information in the following paper chromatogram:

The calculated ${\mathrm{R}}_{\mathrm{f}}$ value of $\mathrm{A} \mathrm{is} \mathrm{\_\_\_\_\_}\times {10}^{-1}$.

Among the given species the Resonance stabilised carbocations are: