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, z will work if and only if z is a nurse. For all z, z will work or z will sleep. For all z, z is a police officer. For all z, if z sleeps, then z is a nurse.
For all z, if z works, then z is a nurse can be inferred via the universal biconditional elimination rule. For all z, if z were a nurse, then z is working can be inferred via the universal biconditional elimination rule.