What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: ~S_2(x) or U_4(x). exists x: S_2(x) or S_1(x). forall x: S_1(x) -> W(x). forall x: U_4(x) -> W(x).
exists x: S_1(x) or U_4(x).