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 not climb a mountain. For all z, z will drive a car if and only if z is an astronaut. For all z, z will climb a mountain or z will drive a car.
For all z, z will drive a car. For all z, if z drives a car, then z is an astronaut. For all z, if z were an astronaut, then z is driving a car.