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_7, x_7 is a server or x_7 is a cashier. For all x_7, x_7 is not a server. For all x_7, x_7 will climb a mountain.
For all x_7, x_7 is a cashier can be inferred via the universal disjunctive syllogism rule.