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 x_8, if x_8 were a police officer, then x_8 is driving a car. There is at least one x_8 for which x_8 is a bartender if and only if x_8 is a police officer. For all x_8, if x_8 drives a car, then x_8 is a bartender.
For all x_8, if x_8 were a police officer, then x_8 is a bartender can be inferred via the universal transitivity rule. There is at least one x_8 for which if x_8 were a bartender, then x_8 is a police officer can be inferred via the existential biconditional elimination rule. There is at least one x_8 for which if x_8 were a police officer, then x_8 is a bartender can be inferred via the existential biconditional elimination rule.