Among the following, the most stable isomer is :

Options

A.
B.
C.
D.

Explanation

To determine the most stable isomer among the given options, we will analyze the potential for hydrogen bonding in each isomer and assess their stability based on the strength of these interactions.

### Step-by-Step Solution:

1. **Identify the Isomers**:
- Let's denote the isomers as A, B, C, and D. We need to analyze the structure of each isomer to understand their potential for hydrogen bonding.

2. **Analyze Hydrogen Bonding**:
- Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (like O, N, or F) and is attracted to another electronegative atom.
- Check each isomer for the presence of -OH or -NH groups, as these can participate in hydrogen bonding.

3. **Evaluate the Distance in Hydrogen Bonding**:
- The stability of hydrogen bonds is influenced by the distance between the hydrogen donor and acceptor.
- Isomers that allow for closer proximity between the hydrogen donor and acceptor will have stronger hydrogen bonds.

4. **Compare the Isomers**:
- **Isomer A**: Analyze the arrangement of atoms and the potential for hydrogen bonding.
- **Isomer B**: Check the positioning of groups and the distance for hydrogen bonding.
- **Isomer C**: Evaluate the hydrogen bonding potential and distance.
- **Isomer D**: Assess the arrangement; if the hydrogen donor and acceptor are close, this is favorable for strong hydrogen bonding.

5. **Determine Stability**:
- Based on the analysis, isomer D has the closest hydrogen bonding interactions, leading to stronger and more stable hydrogen bonds compared to isomers A, B, and C.
- Therefore, isomer D is the most stable due to its optimal hydrogen bonding configuration.

6. **Conclusion**:
- The most stable isomer among the options provided is **isomer D**.