Answer:d). Both have a carbon backbone where a ketose has a ketone group on the second carbon in the molecule, and an aldose has an aldehyde group at the end of the molecule.
Explanation: There are two families of monosaccharides: aldoses and ketoses.
The back-bones of common monosaccharides are unbleached carbon chains in which all the carbon atoms are linked by single bonds. When these monosaccharides are in an open chain form, one of the carbon atoms is double-bonded to an oxygen atom to form a carbonyl group.
When the carbonyl group has a hydrogen atom bonded to it, it is called an aldehyde group and when the carbonyl group is bonded to two carbon atoms, it is called a ketone group.
A Monosaccharide in which the aldehyde group is at the end of the carbon chain of the molecule is called an aldose while a monosaccharide in which the ketone group is on the second carbon atom of the molecule is called a ketose.