Concept:A non-reducing disaccharide has both anomeric carbons involved in the glycosidic bond (acetal linkage).
A reducing disaccharide has at least one free hemiacetal group.
Explanation:Check each structure for a free anomeric carbon.
Structure in option A is sucrose, where glucose (C1) and fructose (C2) are linked via an acetal bond.
Both anomeric carbons are locked, so no free hemiacetal group remains.
Hence sucrose does not reduce Fehling’s or Tollens’ reagent — it is non‑reducing.
Structures in options B, C, and D contain a free hemiacetal, making them reducing sugars.
Answer:Option A
