What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: There is at least one z_1 for which z_1 will drive a car. For all z_1, z_1 is not excited. For all z_1, z_1 is excited or z_1 is a doctor.
For all z_1, z_1 is a doctor can be inferred via the universal disjunctive syllogism rule.