What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z_3, if z_3 sleeps, then z_3 is sad. For all z_3, if z_3 were sad, then z_3 is a police officer. There is at least one z_3 for which if z_3 were sad, then z_3 is sleeping. For all z_3, z_3 is not a police officer.
For all z_3, z_3 is not sad. For all z_3, if z_3 sleeps, then z_3 is a police officer. There is at least one z_3 for which z_3 is sad if and only if z_3 will sleep. There is at least one z_3 for which z_3 will sleep if and only if z_3 is sad.