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: Karen is not making tea or David is a janitor. If David were a janitor, then Jennifer is a scientist. For all x_13, if x_13 were a scientist, then x_13 is sleeping. If Barbara were a cashier, then Jennifer is sleeping. Karen is making tea or Barbara is a cashier.
Barbara is a cashier or David is a janitor can be inferred via the resolution rule.