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_4, if x_4 takes a plane, then x_4 is a musician. For all x_4, if x_4 were an office clerk, then x_4 is a musician. For all x_4, x_4 will listen to a song or x_4 will take a plane. For all x_4, x_4 will not listen to a song.
For all x_4, x_4 will take a plane can be inferred via the universal disjunctive syllogism rule.