What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall z: W_4(z) -> W_2(z). forall z: W_4(z) -> W_2(z). exists z: W_2(z) -> W_4(z).
exists z: W_2(z) <-> W_4(z). exists z: W_2(z) <-> W_4(z). exists z: W_4(z) <-> W_2(z). exists z: W_4(z) <-> W_2(z).