Which of the following pair forms the same osazone with pheny hydrazine

Options

A. `D-` Glucose and `L-` Fructose
B. `D-` Glucose and `L-` Galactose
C. `D-` Glucose and `D-` Mannose
D. Lactose and Maltose

Explanation

To determine which pair forms the same osazone with phenyl hydrazine, we need to analyze the structure of the sugars involved. The osazone formation is a reaction between sugars and phenyl hydrazine, which leads to the formation of a compound known as an osazone.

### Step-by-Step Solution:

1. **Identify the Sugars**: The question mentions three sugars: D-glucose, D-fructose, and D-mannose. We need to analyze their structures to see if they can form the same osazone.

2. **Understand Osazone Formation**: Osazone formation occurs when sugars react with phenyl hydrazine. The reaction typically involves the carbonyl group (aldehyde or ketone) of the sugar. Sugars that yield the same osazone must have similar structures in terms of the arrangement of their functional groups.

3. **Analyze D-Glucose and D-Fructose**:
- **D-Glucose**: It is an aldose (an aldehyde sugar) with the structure:
\[ \text{C}_6\text{H}_{12}\text{O}_6 \]
- **D-Fructose**: It is a ketose (a ketone sugar) with the structure:
\[ \text{C}_6\text{H}_{12}\text{O}_6 \]
- Both sugars have the same molecular formula but differ in the functional group (aldehyde vs. ketone).

4. **Analyze D-Mannose**:
- **D-Mannose**: It is also an aldose similar to D-glucose but differs in the arrangement of hydroxyl groups.
- The structure is:
\[ \text{C}_6\text{H}_{12}\text{O}_6 \]

5. **Compare Structures**:
- D-glucose and D-mannose differ only in the configuration around the second carbon atom.
- D-fructose, being a ketose, has a different structure but can still form the same osazone as D-glucose and D-mannose due to the rearrangement of the carbon skeleton during the reaction.

6. **Conclusion**: D-glucose, D-fructose, and D-mannose can all form the same osazone when treated with phenyl hydrazine. The key is that they have similar arrangements of functional groups that lead to the same product upon reaction with phenyl hydrazine.

### Final Answer:
The pair that forms the same osazone with phenyl hydrazine is D-glucose and D-fructose (and also D-mannose).