What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? t_2 <-> q. p_12 or q. ~p_12 or r_12. r_12 <-> t_2.
q or r_12. t_2 -> q. r_12 -> t_2. q -> t_2. t_2 -> r_12.