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: For all z_4, if z_4 were excited, then z_4 is playing tennis. For all z_4, z_4 is excited. There is at least one z_4 for which z_4 is a doctor.
For all z_4, z_4 will play tennis can be inferred via the universal modus ponens rule. There is at least one z_4 for which z_4 is a doctor and z_4 is excited can be inferred via the existential conjunction rule. There is at least one z_4 for which z_4 is excited and z_4 is a doctor can be inferred via the existential conjunction rule.