Answer
The IUPAC name of the alkene is $penta-1,2,4-triene$
Work Step by Step
The compound has 5 carbon atoms in its longest carbon chain containing the double bond ($pent-$). It has 3 double bonds at positions 1, 2 and 4. So, the IUPAC name of the alkene is $penta-1,2,4-triene$