An organic compound `A(C_(5)H_(8)O_(3))` on heating with soda lime gives B which reacts with HCN to give C. The compound C reacts with thionyl chloride to produce D which on reaction with KCN gives a coompound E. Alkaline hydrolysis of E gives a salt F which on heating with soda lime produces n-butane. Careful oxidation of A with dichromate gives acetic acid and malonic acid. Give the structures from A to F with proper reason.