Which of the following can show tautomerism here.

Options

A.
B.
C.
D. Both B and C

Answer

To determine which compounds can show tautomerism, we need to understand the concept of tautomerism itself. Tautomerism is a type of isomerism that involves the migration of a hydrogen atom and the shifting of a double bond, typically between a keto form (C=O) and an enol form (C=C-OH).

### Step-by-Step Solution:

1. **Understand Tautomerism**:
- Tautomerism involves the 1,3-shift of a hydrogen atom. This means that a hydrogen atom moves from one carbon atom to another, typically resulting in a change from a keto form to an enol form.

2. **Identify the Structures**:
- Look at the given options and identify the structures of each compound. Draw the structures if necessary to visualize the potential for tautomerism.

3. **Analyze Each Option**:
- **Option 1**: Check if the structure allows for the migration of hydrogen. If the structure does not have a keto group or the necessary hydrogen atoms to migrate, it cannot show tautomerism.
- **Option 2**: Determine if the structure contains a keto group and if there is a hydrogen that can migrate to form an enol. If it does, this compound can show tautomerism.
- **Option 3**: Similar to option 2, check for the presence of a keto group and the ability for hydrogen migration.
- **Option 4**: This option may suggest that both Option 2 and Option 3 can show tautomerism. Confirm if both options indeed allow for the necessary hydrogen migration.

4. **Conclusion**:
- After analyzing all options, identify which ones can show tautomerism. Typically, if options 2 and 3 allow for the necessary structural changes, then option 4 (which states both B and C) would be correct.

### Final Answer:
- The compounds that can show tautomerism are those that contain a keto group and have the ability for a hydrogen atom to migrate, typically leading to an enol form. Therefore, the correct answer is **Option 4** (both B and C).