Species which will exhibit geometrical isomerism among the following is/are?

Options

A.
B.
C.
D. `N_(2)H_(2)`

Answer

To determine which species exhibit geometrical isomerism, we will analyze each option provided in the question. Geometrical isomerism occurs in compounds with restricted rotation around a double bond (C=C, C=N, or N=N) and requires different groups attached to the double-bonded atoms.

### Step-by-Step Solution:

1. **Identify the Compounds:**
- We have four options (A, B, C, D) to analyze for geometrical isomerism.

2. **Analyze Option A:**
- The structure contains a C=C double bond with different groups attached: tritium (T), deuterium (D), hydrogen (H), and a methyl group (CH₃).
- Since there are two different groups on each carbon of the double bond, this compound can exhibit geometrical isomerism (E/Z forms).
- **Conclusion:** Option A shows geometrical isomerism.

3. **Analyze Option B:**
- The structure has a carbon with two identical groups (cyclopentyl) and one different group.
- Since one carbon atom has two identical groups, it cannot exhibit geometrical isomerism.
- **Conclusion:** Option B does not show geometrical isomerism.

4. **Analyze Option C:**
- The structure contains a C=N double bond with different groups: H and OH on one side, and CH₃ on the other.
- The presence of different groups allows for the existence of geometrical isomers (cis/trans or syn/anti).
- **Conclusion:** Option C shows geometrical isomerism.

5. **Analyze Option D:**
- The structure is N₂H₂, which has a N=N double bond with two hydrogen atoms.
- The arrangement of hydrogen atoms can lead to syn and anti configurations, indicating the presence of geometrical isomers.
- **Conclusion:** Option D shows geometrical isomerism.

### Final Answer:
The species that exhibit geometrical isomerism among the given options are **A, C, and D**.