What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, if y were a janitor, then y is an office clerk. Thomas is a cashier. For all y, if y were a police officer, then y is an office clerk. For all y, y is a police officer or y is a janitor.
There is at least one x for which x is a cashier. For all y, y is an office clerk.