Answer
$Cl_2$ and $F_2$ are non polar.
$NF_3$ and $ClF$ are polar
Work Step by Step
$Cl_2$ and $F_2$ do not have polar interaction since 2 atoms are the same in each case.
$ClF$ has polar interaction since $F$ is more electronegative than $Cl$.
$NF_3$ has polar interaction due to its structure with the lone pair as shown in structure.
