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 not take a plane. For all x_5, if x_5 were a janitor, then x_5 is a taxi driver. For all x_5, if x_5 were a taxi driver, then x_5 is playing squash. For all x_5, if x_5 plays squash, then x_5 is taking a plane.
For all x_5, x_5 will not play squash can be inferred via the universal modus tollens rule. For all x_5, if x_5 were a janitor, then x_5 is playing squash can be inferred via the universal transitivity rule. For all x_5, if x_5 were a taxi driver, then x_5 is taking a plane can be inferred via the universal transitivity rule.