Out of the following, the alkene that exhibits optical isomerism is:

Optical isomerism in alkenes (without other chiral centers) requires a chiral carbon atom.3-methyl-1-pentene: ${\text{CH}}_2=\text{CH}-{\text{C}}^{\ast }\text{H}({\text{CH}}_3)({\text{CH}}_2{\text{CH}}_3)$. The 3rd carbon is attached to 4 different groups: $-\text{H},-{\text{CH}}_3,-{\text{CH}}_2{\text{CH}}_3$, and $-\text{CH}={\text{CH}}_2$. Thus it is chiral.Other options do not have a chiral center.