What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? q_9 -> p_6. ~p_9 or r_9. p_6 -> q_9. p_9 or q_9. ~p_6.
~q_9. q_9 or r_9. q_9 <-> p_6. p_6 <-> q_9.