What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, if z were a cashier, then z is excited. For all z, z is excited or z is not a cashier. For all z, if z were excited, then z is a cashier.
For all z, if z were a cashier, then z is excited. For all z, z is a cashier if and only if z is excited. For all z, z is excited if and only if z is a cashier.