The reduction of 4-octyne with $H_2$ in the presence of $Pd/BaS{O}_4$ and quinoline gives :

The correct option is B cis-4-octene
Reduction of alkyne with $H_2$ and $Pd/BaS{O}_4$ gives cis-alkene. The reaction is shown below.

The reagent known as Lindlar's catalyst.

Option B is correct.