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: There is at least one x_9 for which x_9 will play a game if and only if x_9 will listen to a song. For all x_9, if x_9 listens to a song, then x_9 is a lawyer. For all x_9, if x_9 drives a car, then x_9 is playing a game.
There is at least one x_9 for which if x_9 plays a game, then x_9 is listening to a song can be inferred via the existential biconditional elimination rule. There is at least one x_9 for which if x_9 listens to a song, then x_9 is playing a game can be inferred via the existential biconditional elimination rule.