Which one of the following is an example of non-reducing sugar?

The correct option is A Sucrose
Sucrose is not a reducing sugar because it lacks the ability to form either aldehyde or a ketone in a basic solution. It cannot perform as a reducing agent in solutions at a pH above 7. Reducing capability is defined by the presence of free or potential aldehyde or ketone group. All monosaccharides have free ketone or aldehyde group. This means that they are all reducing sugars. Sucrose's anomeric carbon is not free since this carbon is used to link fructose and glucose together therefore, this anomeric carbon can't open up the ring structure and react with the reagent.