Please answer question below in regards 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$,B,C$ and foo $(x,Y,Z),$ select the term that is a unifier.

foo$(D,E,F)$

foo$(bar,$ baz, quux$)$

foo$(U,U,U)$

foo$(X,A,C)$

All of the above

None of the above