In which of following sets the carbohydrates are reducing sugar

Options

A. glucose , fructose , sucrose ,
B. maltose , lactose , sucrose
C. cellulose , sucrose , starch
D. maltose , lactose , fructose

Answer

To determine which set of carbohydrates contains reducing sugars, we need to analyze each option based on the presence of a free aldehyde group (CHO) or a hemiacetal linkage. Reducing sugars can reduce certain reagents, such as Tollens' reagent and Fehling's solution, due to the presence of these functional groups.

### Step-by-Step Solution:

1. **Understanding Reducing Sugars**:
- Reducing sugars are carbohydrates that can donate electrons to other molecules, which is typically due to the presence of a free aldehyde group (CHO) or a hemiacetal linkage.

2. **Analyzing Each Set**:
- **Set 1: Glucose, Fructose, Sucrose**
- Glucose: Has a free aldehyde group (CHO) → Reducing sugar.
- Fructose: Can tautomerize to form a free aldehyde group → Reducing sugar.
- Sucrose: No free aldehyde group or hemiacetal linkage → Non-reducing sugar.
- **Conclusion**: This set contains 2 reducing sugars (Glucose and Fructose) and 1 non-reducing sugar (Sucrose).

- **Set 2: Maltose, Lactose, Sucrose**
- Maltose: Contains a hemiacetal linkage → Reducing sugar.
- Lactose: Contains a hemiacetal linkage → Reducing sugar.
- Sucrose: No free aldehyde group or hemiacetal linkage → Non-reducing sugar.
- **Conclusion**: This set contains 2 reducing sugars (Maltose and Lactose) and 1 non-reducing sugar (Sucrose).

- **Set 3: Cellulose, Sucrose, Starch**
- Cellulose: Polysaccharide, does not have free aldehyde groups → Non-reducing sugar.
- Sucrose: No free aldehyde group or hemiacetal linkage → Non-reducing sugar.
- Starch: Polysaccharide, does not have free aldehyde groups → Non-reducing sugar.
- **Conclusion**: This set contains only non-reducing sugars.

- **Set 4: Maltose, Lactose, Sucrose**
- Maltose: Contains a hemiacetal linkage → Reducing sugar.
- Lactose: Contains a hemiacetal linkage → Reducing sugar.
- Sucrose: No free aldehyde group or hemiacetal linkage → Non-reducing sugar.
- **Conclusion**: This set contains 2 reducing sugars (Maltose and Lactose) and 1 non-reducing sugar (Sucrose).

3. **Final Assessment**:
- The sets that contain reducing sugars are:
- Set 1: 2 reducing sugars
- Set 2: 2 reducing sugars
- Set 4: 2 reducing sugars
- Set 3 contains only non-reducing sugars.

### Answer:
The correct answer is **Set 1, Set 2, and Set 4** contain reducing sugars.