What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y_2: P_3(y_2) -> S_4(y_2). forall y_2: S_4(y_2) <-> P_3(y_2). exists y_2: S_4(y_2) -> P_3(y_2).
exists y_2: S_4(y_2) <-> P_3(y_2). exists y_2: P_3(y_2) <-> S_4(y_2). forall y_2: S_4(y_2) -> P_3(y_2). forall y_2: P_3(y_2) -> S_4(y_2).