What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_17: R_2(x_17) <-> S_17(x_17). S_17(c) or ~u. u.
u -> S_17(c). forall x_17: R_2(x_17) -> S_17(x_17). forall x_17: S_17(x_17) -> R_2(x_17).