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_5, x_5 will climb a mountain or x_5 will take a plane. There is at least one x_5 for which if x_5 were bored, then x_5 is not taking a plane. For all x_5, if x_5 climbs a mountain, then x_5 is a scientist. For all x_5, x_5 is not a scientist.
For all x_5, x_5 will not climb a mountain can be inferred via the universal modus tollens rule.