An organic compound ' A ' $\left(\mathrm{C}_9 \mathrm{H}_{10} \mathrm{O}\right)$ when treated with conc. HI undergoes cleavage to yield compounds ' B ' and ' C '. ' B ' gives yellow precipitate with AgNO 3 where as ' C ' tautomerizes to 'D'. 'D' gives positive iodoform test. 'A' could be
