The number of geometrical isomers possible for the compound, $\mathrm{CH}_3 \mathrm{CH}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}_2$ is

Although $\mathrm{CH}_3 \mathrm{C}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}_2$ has two double bond but one of them has two similar atoms (i.e. H -atom) therefore no geometrical isomerism is possible around the double bond. However each carbon atom of other double bond has two different atoms/groups and hence geometrical isomerism is possible around this double bond. Hence, only two geometrical isomers are possible.