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 y_2, if y_2 makes tea, then y_2 is a police officer. For all y_2, if y_2 were a police officer, then y_2 is playing a game. There is at least one y_2 for which if y_2 were a police officer, then y_2 is making tea. For all y_2, y_2 will not play a game. For all y_2, if y_2 plays a game, then y_2 is a police officer.
For all y_2, y_2 is not a police officer can be inferred via the universal modus tollens rule. For all y_2, if y_2 makes tea, then y_2 is playing a game can be inferred via the universal transitivity rule. There is at least one y_2 for which if y_2 plays a game, then y_2 is making tea can be inferred via the existential transitivity rule. For all y_2, y_2 is a police officer if and only if y_2 will play a game can be inferred via the universal biconditional introduction rule. For all y_2, y_2 will play a game if and only if y_2 is a police officer can be inferred via the universal biconditional introduction rule. There is at least one y_2 for which y_2 is a police officer if and only if y_2 will make tea can be inferred via the existential biconditional introduction rule. There is at least one y_2 for which y_2 will make tea if and only if y_2 is a police officer can be inferred via the existential biconditional introduction rule.