Which of the following is/are non-reducing sugars?

Options

A. Fructose
B. Glucose
C. Sucrose
D. Lactose

Answer

To determine which of the following sugars are non-reducing, we need to analyze the options: fructose, glucose, sucrose, and lactose.

### Step-by-Step Solution:

1. **Understanding Reducing and Non-Reducing Sugars**:
- Reducing sugars are those that have a free aldehyde (CHO) or ketone group that can donate electrons to reduce another molecule.
- Non-reducing sugars do not have a free aldehyde or ketone group because their anomeric carbon is involved in glycosidic bonds.

2. **Analyzing Each Sugar**:
- **Fructose**: This is a ketose sugar and has a free ketone group, making it a reducing sugar.
- **Glucose**: This is an aldose sugar and has a free aldehyde group, so it is also a reducing sugar.
- **Sucrose**: This is a disaccharide formed from glucose and fructose. In sucrose, both anomeric carbons (from glucose and fructose) are involved in the glycosidic bond, meaning there is no free aldehyde or ketone group. Therefore, sucrose is a non-reducing sugar.
- **Lactose**: This is a disaccharide composed of glucose and galactose. It has a free aldehyde group from glucose, making it a reducing sugar.

3. **Conclusion**:
- From the analysis, the only non-reducing sugar among the options is sucrose.

### Final Answer:
The non-reducing sugar is **sucrose** (Option C).

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