A compound with `MF-C_3H_6O` gives+ve iodoform test. Name the compound.

A compound gives +ve iodoform test and +ve Fehling's test. The compound is

An organic compound A having molecular formula C_(2)H_(5)O_(2)N on treatment with HNO_(2) gives a blue coloured compound B having molecular formula C_(2)H_(4)O_(3)N_(2) . On reduction, A gives a compound C having molecular formula C_(2)H_(7)N . C on treatment with nitrous acid gives D which gives positive iodoform test. Identify the compounds A, B, C and D.