Geometrical isomerism is shown by ?

Options

A.
B.
C.
D. `Ph-CH=CH-CH_3`

Explanation

To determine which compounds exhibit geometrical isomerism, we need to analyze the presence of double bonds and the arrangement of groups around those double bonds. Here’s a step-by-step solution:

### Step 1: Understand Geometrical Isomerism
Geometrical isomerism occurs due to the restricted rotation around a double bond (C=C) or within a ring structure. For geometrical isomers to exist, there must be two different groups attached to each carbon of the double bond.

**Hint:** Look for double bonds or rings in the compounds, as these are necessary for geometrical isomerism.

### Step 2: Analyze Each Option
- **Option A:** Check for double bonds. If there are only single bonds, geometrical isomerism cannot occur.

**Hint:** Single bonds allow free rotation, which prevents isomerism.

- **Option B:** Identify if there is a double bond and if the carbons have different groups attached. If both carbons of the double bond have the same groups, geometrical isomerism cannot occur.

**Hint:** Ensure both carbons in the double bond have different substituents for isomerism to be possible.

- **Option C:** Similar to option B, check the groups attached to the double bond. If they are the same on one side, geometrical isomerism is not possible.

**Hint:** Look for unique groups on both sides of the double bond.

- **Option D:** Examine the structure carefully. If both carbons of the double bond have different groups, then geometrical isomerism can occur.

**Hint:** Identify if there are two different groups on each carbon of the double bond.

### Step 3: Conclusion
After analyzing all options:
- Option A does not show geometrical isomerism due to the absence of double bonds.
- Option B does not show geometrical isomerism because the groups are not different on one side of the double bond.
- Option C also fails to show geometrical isomerism for similar reasons.
- Option D shows geometrical isomerism because both carbons in the double bond have different groups attached.

**Final Answer:** Option D shows geometrical isomerism.