What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~p_8. p_8 <-> q_8. p_4 <-> q_8. p_4 <-> u_4.
p_8 -> q_8. p_4 -> q_8. p_4 -> u_4. q_8 -> p_8. q_8 -> p_4. u_4 -> p_4. ~q_8.