What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one z for which z is rich. For all z, z will not drive a car. For all z, z will not read a book or z will write a letter. For all z, z will read a book or z will drive a car.
For all z, z will drive a car or z will write a letter.