Which of the following is least stable ?

Options

A. `Me - O- overset (Ө) CH_2`
B.
C. `PhC overset (Ө) H_2`
D. .

Explanation

To determine which carbanion is the least stable among the given options, we need to analyze the resonance stability of each carbanion. Carbanions are negatively charged carbon species, and their stability can often be enhanced through resonance.

### Step-by-Step Solution:

1. **Identify the Carbanions**:
We need to look at the structures of the carbanions provided in the options (let's assume we have options A, B, C, and D).

2. **Analyze Resonance**:
- **Option A**: Check if it has any resonance structures. If it does not have any pi bonds or adjacent electronegative atoms to delocalize the negative charge, it will be less stable.
- **Option B**: Check if it can participate in resonance. If there are pi bonds or adjacent atoms that can stabilize the negative charge through resonance, it will be more stable.
- **Option C**: Similar to option B, check for resonance. If it can delocalize the negative charge, it will be more stable.
- **Option D**: Again, check for resonance. If it has a structure that allows for delocalization of the negative charge, it will be more stable.

3. **Compare Stability**:
- The carbanion that does not have any resonance structures (like option A) will be the least stable because it cannot delocalize the negative charge.
- The carbanions that can participate in resonance (like options B, C, and D) will be more stable due to the delocalization of the negative charge.

4. **Conclusion**:
Based on the analysis, the carbanion in **Option A** is the least stable because it does not have the ability to delocalize the negative charge through resonance.

### Final Answer:
The least stable carbanion is **Option A**.