A organic compound X (C4H4O) gives 24 DNP test, but does not reduce fehlig solution. The compound?

... when passed through red hot cu it form Y(C4H11O). When Y on treatment with concentrated with H2SO4 it form Z(C4H4). Z on treatment with HBr form addition product (A) a on treatment with KCN and followed by reduction form( B)(C5H14)write the structure of X Y Z A and B and write the chemical equation involved