Answer
The IUPAC name of the alkene is $(3Z,5Z)-6-chloro-3-(chloromethyl)-octa-1,3,5-triene$
Work Step by Step
The compound has 8 carbon atoms in its longest carbon chain containing the double bond ($oct−$). It has a $chloromethyl−$ substituent at position 3, a $chloro-$ substituent at position 6 and 3 double bonds at positions 1,3 and 5. The bond at position 3 is of $Z$ stereo isomerism and the bond at position 5 is of $Z$ stereo isomerism. So, the IUPAC name of the alkene is $(3Z,5Z)-6-chloro-3-(chloromethyl)-octa-1,3,5-triene$