A compound $\mathrm{A}$ $\left({\mathrm{C}}_2{\mathrm{H}}_6\mathrm{O}\right)$ on oxidation by PCC gave $\mathrm{B}$, which on treatment with aqueous alkali and subsequent heating furnished $\mathrm{C}$. $\mathrm{B}$ on oxidation by ${\mathrm{KMnO}}_4$, forms a monobasic carboxylic acid with molar mass $60 {\mathrm{gmol}}^{-1}$. Deduce the structures of $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$.