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_6, x_6 will play tennis or x_6 is a janitor. There is at least one x_6 for which x_6 will drive a car. For all x_6, if x_6 were a janitor, then x_6 is not driving a car. For all x_6, x_6 will not play tennis or x_6 will sleep.
There is at least one x_6 for which x_6 is not a janitor can be inferred via the existential modus tollens rule. For all x_6, x_6 is a janitor or x_6 will sleep can be inferred via the universal resolution rule.