O.I. (Optical Isomerism) requires a chiral center (asymmetric carbon). G.I. (Geometrical Isomerism) requires restricted rotation (e.g., a double bond or ring) and two different groups on each carbon.

The compound that can show both must have a chiral center and a structural feature allowing geometrical isomerism. The correct structure is the one with a double bond (for G.I.) and a chiral carbon atom (for O.I.). This is the third option: an alkene with four different substituents, including an asymmetric carbon.

Final Answer: The third compound (image with double bond and chiral center).