So in this particular molecule, we don't have that. But in this particular molecule, if we examine this carbon, we have four different groups attached to this carbon. So we have the hydroxyl, we have the H atom, we have this group here and this group here. And so what that means is there will be an enantomer that will exist with respect to this carbon. And this is the Nantomer shown here. So the D glycoaldehyde simply means that it's one of the Nantomers.