What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? William is not a nurse. If William were a nurse, then Michael is sad. For all x_1, x_1 is a janitor if and only if x_1 is sad. If Michael were sad, then William is a nurse.
Michael is not sad. For all x_1, if x_1 were a janitor, then x_1 is sad. For all x_1, if x_1 were sad, then x_1 is a janitor.