Determine if galactobiose is a reducing sugar. Explain your answer.

• A. Galactobiose is a reducing sugar because one of its galactose units has a free anomeric carbon that can act as a reducing agent.
• B. Galactobiose is a reducing sugar because both of its galactose units have free hydroxyl groups that can participate in redox reactions.
• C. Galactobiose is not a reducing sugar because both of its galactose units are linked by an α(1→4) glycosidic bond, which prevents any free anomeric carbons.
• D. Galactobiose is not a reducing sugar because it does not contain any glucose molecules necessary for reducing activity.

Answer: (A)