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_5, if x_5 plays tennis, then x_5 is playing a game. There is at least one x_5 for which x_5 will take a plane if and only if x_5 will play tennis. For all x_5, if x_5 plays a game, then x_5 is playing tennis. For all x_5, x_5 will not play a game.
For all x_5, x_5 will not play tennis can be inferred via the universal modus tollens rule. For all x_5, x_5 will play tennis if and only if x_5 will play a game can be inferred via the universal biconditional introduction rule. For all x_5, x_5 will play a game if and only if x_5 will play tennis can be inferred via the universal biconditional introduction rule. There is at least one x_5 for which if x_5 takes a plane, then x_5 is playing tennis can be inferred via the existential biconditional elimination rule. There is at least one x_5 for which if x_5 plays tennis, then x_5 is taking a plane can be inferred via the existential biconditional elimination rule.