An organic compound with the formula C6H12O6  forms a yellow crystalline solid with phenyl hydrazine and gives a mixture of sorbitol and mannitol when reduced with sodium. Which among the following could be the compound

Since the compound forms a yellow crystalline solid, i.e. osazone with phenyl hydrazine, it may be an aldohexose or a ketohexose, Further, since on reduction, compound forms a mixture of sorbitol and mannitol, it must be a ketohexose, i.e. fructose. Recall that glucose on reduction gives only one alcohol glucitol (Sorbitol)