The correct option is D CuO to convert it into CO2 which turns lime water milky
The given organic compound is mixed with dry copper oxide (CuO) and heated in a hard glass tube. The products of the reaction are passed over (white) anhydrous copper sulphate and then bubbled through lime water. If copper sulphate turns blue due to the formation of CuSO4.5H2O (by water vapor) then the compound contains hydrogen. If lime water is turned milky by CO2, then the compound contains carbon.