What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: q <-> w. r_3 -> w. q -> r_3. ~r_3.
~q can be inferred via the modus tollens rule. q -> w can be inferred via the transitivity rule. q -> w can be inferred via the biconditional elimination rule. w -> q can be inferred via the biconditional elimination rule.