In which of the following keto from is more dominating than enol from :

Options

A.
B.
C.
D. All of these

Explanation

To determine which keto form is more stable than the enol form among the given options, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Keto and Enol Forms**:
- Keto form refers to the carbonyl structure (C=O) while the enol form has a hydroxyl group (–OH) adjacent to a double bond (C=C).
- Generally, keto forms are more stable than enol forms due to the stability of the carbonyl group.

2. **Analyzing Each Option**:
- **Option 1**:
- The keto form is stable, but when converted to the enol form, it forms an anti-aromatic compound.
- Anti-aromatic compounds are less stable due to their violation of Huckel's rule (4n+2 π electrons). Thus, the keto form is more stable than the enol form.

- **Option 2**:
- The keto form is again stable, but the enol form has bulky groups that hinder its stability.
- The steric hindrance from bulky groups makes the enol form less stable compared to the keto form. Therefore, the keto form dominates.

- **Option 3**:
- The keto form is stable, but when converted to the enol form, it violates the Bredt's rule, which states that a double bond cannot be formed at a bridgehead position in bicyclic compounds.
- This violation leads to an unstable enol form, making the keto form more stable.

- **Option 4**:
- Similar to option 3, the keto form is stable, and the enol form violates stability rules, making it less favorable.
- Thus, the keto form is more stable than the enol form in this case as well.

3. **Conclusion**:
- After analyzing all four options, we find that in all cases, the keto form is more stable than the enol form due to various reasons such as anti-aromaticity, steric hindrance, and rule violations.

### Final Answer:
In all the options provided, the keto form is more dominating than the enol form.

---