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_3, if x_3 climbs a mountain, then x_3 is curious. For all x_3, if x_3 sleeps, then x_3 is climbing a mountain.
For all x_3, if x_3 sleeps, then x_3 is curious can be inferred via the universal transitivity rule.