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: s -> q_3. ~q_3. s_4. w_4 -> ~s_4.
~s can be inferred via the modus tollens rule. ~w_4 can be inferred via the modus tollens rule. ~q_3 and s_4 can be inferred via the conjunction rule. s_4 and ~q_3 can be inferred via the conjunction rule.