Out of the following reducing sugars are?

(A) Sucrose

(B) Lactose

(C) Maltose

(D) Cellobiose

B, C, D

The correct answer is option 3. B, C, D.

A. Sucrose: While sucrose is a common sugar found in many plants, it is a non-reducing sugar. It does not have a free aldehyde or ketone group, which is necessary for it to act as a reducing agent.

B. Lactose: Lactose is a disaccharide composed of glucose and galactose units. It contains a free anomeric carbon in the galactose unit, which allows it to act as a reducing sugar.

C. Maltose: Maltose is a disaccharide composed of two glucose units. It contains a free anomeric carbon in one of the glucose units, making it a reducing sugar.

D. Cellobiose: Cellobiose is also a disaccharide composed of two glucose units. Like maltose, it contains a free anomeric carbon in one of the glucose units, allowing it to act as a reducing sugar.

So, options  B, C and D  are all examples of reducing sugars. Option D, cellobiose, is also a reducing sugar, but it's not listed in any of the given options.