If $X=\{a,b,c,d\}$ and $Y=\{f,b,d,g\}$,find (ii) $Y-X$

Question

$\begin{array}{1 1}(A)\;\{f,b,d,g\}&(B)\;\{f,g\}\\(C)\;\{a,b,c,d\}&(D)\;\phi\end{array}$