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_10, x_10 is an astronaut. For all x_10, if x_10 were a police officer, then x_10 is taking a plane. For all x_10, x_10 is a police officer or x_10 will climb a mountain. There is at least one x_10 for which if x_10 climbs a mountain, then x_10 is taking a plane.
There is at least one x_10 for which x_10 will take a plane can be inferred via the existential disjunction elimination rule.