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: ~u_2 or t. u. r. w -> ~r. u_2 or w.
~w can be inferred via the modus tollens rule. u and r can be inferred via the conjunction rule. r and u can be inferred via the conjunction rule. w or t can be inferred via the resolution rule.