Please answer questions below in regaurds to programming language prolog:A unifier of two terms is a term that is an instance of both terms, meaning it can be obtained by substituting variables.

Given Prolog terms foo$($A$,$ A$,$ B$)$ and foo$($X$,$ Y$,$ Y$),$ select the term that is a unifier.

foo$(D,E,F)$

foo$(Z,Z,Z)$

foo$(X,B,B)$

foo$(A,A,Y,Y)$

All of the above

None of the above