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_13, x_13 will take a plane. For all x_13, x_13 will climb a mountain. For all x_13, if x_13 climbs a mountain, then x_13 is a sailor.
For all x_13, x_13 is a sailor can be inferred via the universal modus ponens rule. For all x_13, x_13 will take a plane and x_13 will climb a mountain can be inferred via the universal conjunction rule. For all x_13, x_13 will climb a mountain and x_13 will take a plane can be inferred via the universal conjunction rule.