It is a form of isomerism displayed by unsaturated compounds or by ring compounds, where rotation about carbon bond is restricted C2Fâ‹…Clâ‹…Brâ‹…I also show geometrical isomerism as follows.
Hence, C2Fâ‹…Clâ‹…Brâ‹…I has six geometrical isomers and therefore, option (c) is the correct answer.