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, x_8 is a police officer if and only if x_8 is a lawyer. For all x_8, if x_8 were a police officer, then x_8 is playing a game. For all x_8, x_8 will not play a game.
For all x_8, x_8 is not a police officer can be inferred via the universal modus tollens rule. For all x_8, if x_8 were a police officer, then x_8 is a lawyer can be inferred via the universal biconditional elimination rule. For all x_8, if x_8 were a lawyer, then x_8 is a police officer can be inferred via the universal biconditional elimination rule.