What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_17, x_17 is a janitor or x_17 is not a cashier. For all x_17, x_17 is a cashier. For all x_17, if x_17 listens to a song, then x_17 is a janitor.
For all x_17, if x_17 were a cashier, then x_17 is a janitor.