The molecule among the following that has the hybridization ${\mathrm{sp}}^2, {\mathrm{sp}}^2, \mathrm{sp},\; and \mathrm{sp}$ from left to right atoms is:

1. $\mathrm{HC}\equiv \mathrm{C}-\mathrm{C}\equiv \mathrm{H}$

2. ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{C}\equiv \mathrm{CH}$

3. ${\mathrm{CH}}_2=\mathrm{CH}-\mathrm{CH}={\mathrm{CH}}_2$ 

4. ${\mathrm{CH}}_2-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_3$

In the given hydrocarbon, 

 
The state of hybridization of carbons 1, 3, and 5 are:

1. sp², sp, sp³

2. sp, sp³, sp²

3. sp, sp², sp³

4. sp³, sp², sp

A compound possessing optical isomerism provided it has the molecular formula C₇H₁₆, would be: