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 will drive a car if and only if z is a writer. There is at least one z for which if z takes a plane, then z is a writer. For all z, z will listen to a song or z will not drive a car.
For all z, if z drives a car, then z is listening to a song. For all z, if z drives a car, then z is a writer. For all z, if z were a writer, then z is driving a car.