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_1, if x_1 were a doctor, then x_1 is a cashier. For all x_1, if x_1 were bored, then x_1 is a janitor. There is at least one x_1 for which x_1 is a doctor or x_1 is bored. For all x_1, if x_1 were a janitor, then x_1 is a cashier.
For all x_1, if x_1 were bored, then x_1 is a cashier can be inferred via the universal transitivity rule.