Which of the following compounds can exhibit geometrical isomerism?

Options

A.
B.
C.
D. `C_2H_5-CH = CH - CH = CH`

Explanation

To determine which compounds can exhibit geometrical isomerism, we need to analyze the given options based on the presence of double bonds and the arrangement of substituents around those double bonds. Geometrical isomerism occurs when there is restricted rotation around a double bond, leading to different spatial arrangements of groups attached to the carbon atoms involved in the double bond.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Let's denote the four compounds as A, B, C, and D.

2. **Analyze Compound A**:
- Check for double bonds and the substituents on the carbon atoms involved in the double bond.
- If both carbon atoms in the double bond have two different substituents, geometrical isomerism is possible.
- **Conclusion**: Compound A can exhibit geometrical isomerism.

3. **Analyze Compound B**:
- This compound is an Alene system, which typically has multiple double bonds.
- In Alene systems with an even number of double bonds, geometrical isomerism is not possible due to symmetry.
- **Conclusion**: Compound B cannot exhibit geometrical isomerism.

4. **Analyze Compound C**:
- This is another Alene system but has an odd number of double bonds.
- Check the sp² carbon atoms for different substituents.
- If the sp² carbon atoms have different substituents, geometrical isomerism is possible.
- **Conclusion**: Compound C can exhibit geometrical isomerism.

5. **Analyze Compound D**:
- Look at the double bond and the substituents on the carbon atoms.
- If both carbon atoms in the double bond have two different substituents, geometrical isomerism can occur.
- **Conclusion**: Compound D can exhibit geometrical isomerism.

6. **Final Summary**:
- Based on the analysis, compounds A, C, and D can exhibit geometrical isomerism, while compound B cannot.

### Final Answer:
The compounds that can exhibit geometrical isomerism are A, C, and D.