Which one of the following expressions does NOT represent exclusive NOR of $x$ and $y$?
$A$ : means both are either true OR both are false. then it will be true = ExNOR
$B$ & $C$ : whenever any one of the literal is complemented then ExOR can be turned to ExNOR and complement sign on the literal can be removed. So these two also represents ExNOR operation of $x$ and $y$.
Answer is option D. It is the ExOR operation b/w the two.