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 will listen to a song or x_8 will write a letter. For all x_8, x_8 will take a plane. For all x_8, if x_8 listens to a song, then x_8 is playing tennis. There is at least one x_8 for which if x_8 writes a letter, then x_8 is playing tennis.
There is at least one x_8 for which x_8 will play tennis can be inferred via the existential disjunction elimination rule.