Assertion: Sucrose is a non reducing sugar.
Reason : Sucrose is a disaccharide formed by glycosidic linkage between C-1 of `alpha`-glucose and C-2 of `beta`-fructose.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Sucrose is a non-reducing sugar."
- To determine if this is true, we need to understand what a non-reducing sugar is. Non-reducing sugars do not have free aldehyde or ketone groups that can act as reducing agents.

2. **Analyzing Sucrose**:
- Sucrose is a disaccharide composed of two monosaccharides: glucose and fructose.
- Specifically, it is formed by a glycosidic linkage between the C-1 of alpha-glucose and the C-2 of beta-fructose.

3. **Identifying the Glycosidic Linkage**:
- The glycosidic bond in sucrose involves the anomeric carbon (C-1) of alpha-glucose and the anomeric carbon (C-2) of beta-fructose.
- This linkage effectively locks the functional groups of both sugars, preventing them from being free to participate in redox reactions.

4. **Conclusion on the Assertion**:
- Since sucrose does not have any free aldehyde or ketone groups due to the formation of the glycosidic bond, it cannot act as a reducing agent.
- Therefore, the assertion that "Sucrose is a non-reducing sugar" is correct.

5. **Understanding the Reason**:
- The reason states that "Sucrose is a disaccharide formed by glycosidic linkage between C-1 of alpha-glucose and C-2 of beta-fructose."
- This statement is accurate as it correctly describes the structure of sucrose.

6. **Conclusion on the Reason**:
- The reason provided explains why sucrose is a non-reducing sugar, as the glycosidic linkage prevents the presence of free aldehyde or ketone groups.

7. **Final Evaluation**:
- Both the assertion and the reason are correct, and the reason correctly explains the assertion.
- Thus, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.