The reagent which does not react with both, acetophenone and benzaldehyde is

Options

A. Sodium hydrogensulfite
B. Phenylhydrazine
C. Fehling's solution
D. Grignard reagent

Explanation

To solve the question of which reagent does not react with both acetophenone and benzaldehyde, we need to analyze the nature of these compounds and the reagents mentioned.

### Step 1: Identify the Compounds
- **Acetophenone**: The structure is represented as CH₃C(=O)C₆H₅. It is a ketone.
- **Benzaldehyde**: The structure is represented as C₆H₅CHO. It is an aldehyde.

### Step 2: Understand the Reactivity of the Compounds
- Aldehydes (like benzaldehyde) are generally more reactive than ketones (like acetophenone) towards certain reagents due to the presence of a hydrogen atom attached to the carbonyl carbon in aldehydes.
- Both acetophenone and benzaldehyde contain a carbonyl group (C=O) which can participate in various reactions.

### Step 3: List Common Reagents and Their Reactivity
1. **Sodium Hydrogen Sulfide (NaHS)**: Reacts with both aldehydes and ketones, forming thiohemiacetals.
2. **Phenylhydrazine**: Reacts with both aldehydes and ketones to form hydrazones.
3. **Grignard Reagents (RMgX)**: Reacts with both aldehydes and ketones to form alcohols.
4. **Fehling's Solution**: This reagent contains copper(II) ions and primarily reacts with aldehydes. It does not react with ketones.

### Step 4: Determine the Non-Reactive Reagent
From the analysis:
- **Fehling's Solution** does not react with benzaldehyde (an aldehyde) because it specifically does not react with benzaldehyde, and it also does not react with acetophenone (a ketone).

### Conclusion
The reagent that does not react with both acetophenone and benzaldehyde is **Fehling's Solution**.

### Final Answer
**Fehling's Solution**