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_4 for which x_4 will not listen to a song or x_4 is a scientist. For all x_4, if x_4 climbs a mountain, then x_4 is working. For all x_4, x_4 will not work. For all x_4, x_4 will listen to a song or x_4 will climb a mountain.
For all x_4, x_4 will not climb a mountain can be inferred via the universal modus tollens rule. There is at least one x_4 for which x_4 will climb a mountain or x_4 is a scientist can be inferred via the existential resolution rule.