Number of geometrical isomers of the given compound are:

${\mathrm{CH}}_3-\mathrm{CH}=\mathrm{C}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}-\mathrm{Cl}$

Cumulative diene does not show G.I.

$\text{ No.of }\mathrm{G}.\mathrm{I}=2^{\mathrm{n}}=2^1=2\text{ ( }\mathrm{n}=\text{ no. of double bonds) }$