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, z_4 will drive a car if and only if z_4 is a soldier. For all z_4, z_4 will drive a car or z_4 is not a doctor.
For all z_4, if z_4 were a doctor, then z_4 is driving a car can be inferred via the universal rewriting rule. For all z_4, if z_4 drives a car, then z_4 is a soldier can be inferred via the universal biconditional elimination rule. For all z_4, if z_4 were a soldier, then z_4 is driving a car can be inferred via the universal biconditional elimination rule.