What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_3, y_3 will cook or y_3 is a nurse. There is at least one y_3 for which y_3 will not cook or y_3 is a janitor. For all y_3, y_3 is a nurse if and only if y_3 will work. For all y_3, if y_3 were a janitor, then y_3 is working.
There is at least one y_3 for which y_3 is a nurse or y_3 is a janitor. For all y_3, if y_3 were a nurse, then y_3 is working. For all y_3, if y_3 works, then y_3 is a nurse.