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_6 -> r_6. t or q_6. s. t -> r_6. p_12 -> ~s.
~p_12 can be inferred via the modus tollens rule. r_6 can be inferred via the disjunction elimination rule.