What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, z is a bartender if and only if z will drive a car. For all z, if z were a lawyer, then z is driving a car. For all z, if z were a police officer, then z is a lawyer. There is at least one z for which z is a bartender or z is a police officer.
For all z, if z were a police officer, then z is driving a car. For all z, if z were a bartender, then z is driving a car. For all z, if z drives a car, then z is a bartender.