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 -> r_3. r_3 -> t. t -> q. ~r. t -> r.
~t can be inferred via the modus tollens rule. q -> t can be inferred via the transitivity rule. r_3 -> q can be inferred via the transitivity rule. r_3 -> r can be inferred via the transitivity rule. t -> r_3 can be inferred via the transitivity rule.