$A$ similarity between optical and geometrical isomerism is that

Consider the sets $I$,$II$,and $III$. Identify the set$(s)$ which is (are) correctly matched.
$I$. $\text{Staggered ethane} > \text{eclipsed ethane} \dots \dots \dots \text{torsional strain}$.
$II$. $2, 2-\text{Dimethylbutane} > 2-\text{methylpentane} \dots \dots \dots \text{boiling point}$.
$III$. $cis-\text{but}-2-\text{ene} > trans-\text{but}-2-\text{ene} \dots \dots \dots \text{dipole moment}$.

Which of the following pairs represents types of stereoisomerism?

$Ph-C(ClF_2)=C(F)_2 \xrightarrow{1\,eq. \, ^-OEt} A$ (major product),$A$ is

The reaction $\text{spiro[3.3]hept-1-ene} \xrightarrow{H^+, \Delta} A$. The product $A$ is:

Examine the following three pairs of possible isomers. Now state whether the pairs represent identical compounds or different isomers.