Which of following will show tautomerism :-

Options

A.
B.
C.
D. All of these

Answer

To determine which of the given compounds shows tautomerism, we need to understand the concept of tautomerism and identify the presence of hydrogen atoms that can shift positions between different forms of the compound.

### Step-by-Step Solution:

1. **Understand Tautomerism**: Tautomerism is a type of isomerism where a compound can exist in two or more interconvertible forms, typically differing in the position of a hydrogen atom and a double bond. The most common example is keto-enol tautomerism.

2. **Identify the Compounds**: Look at the given options (not provided here, but typically they would be chemical structures). For each compound, we need to analyze the presence of hydrogen atoms and the possibility of their movement.

3. **Check for Hydrogen Atoms**: Examine each compound to see if there are hydrogen atoms that can shift. Tautomerism requires at least one hydrogen atom that can move from one atom to another.

4. **Analyze the Structures**:
- For each compound, if there is a hydrogen atom that can migrate (for example, from a carbon to an oxygen atom), then that compound can show tautomerism.
- If a compound does not have any hydrogen atoms that can shift, it cannot exhibit tautomerism.

5. **Conclusion**: Based on the analysis, identify which compound(s) can show tautomerism. If only one of the options has the required hydrogen atom that can shift, then that is the correct answer.

### Example Analysis:
- **Compound A**: No hydrogen atoms present → Cannot show tautomerism.
- **Compound B**: Has a hydrogen atom that can shift between two different atoms (e.g., from carbon to oxygen) → Can show tautomerism.
- **Compound C**: No hydrogen atoms present → Cannot show tautomerism.
- **Compound D**: Has a hydrogen atom that can shift → Can show tautomerism.

Thus, the correct answer would be the compound(s) that can show tautomerism based on the presence of movable hydrogen atoms.