$A$ compound $X$ is formed by the reaction of a carboxylic acid $C_{2}H_{4}O_{2}$ and an alcohol in the presence of a few drops of $H_{2}SO_{4}$. The alcohol,upon oxidation with alkaline $KMnO_{4}$ followed by acidification,gives the same carboxylic acid as used in this reaction. Give the names and structures of $(a)$ carboxylic acid,$(b)$ alcohol,and $(c)$ the compound $X$. Also,write the chemical reaction.