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_6 for which if x_6 plays tennis, then x_6 is listening to a song. For all x_6, if x_6 drives a car, then x_6 is playing tennis. For all x_6, x_6 is a sailor or x_6 will drive a car. For all x_6, x_6 will listen to a song if and only if x_6 is a sailor.
There is at least one x_6 for which if x_6 drives a car, then x_6 is listening to a song can be inferred via the existential transitivity rule. For all x_6, if x_6 listens to a song, then x_6 is a sailor can be inferred via the universal biconditional elimination rule. For all x_6, if x_6 were a sailor, then x_6 is listening to a song can be inferred via the universal biconditional elimination rule.