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 an office clerk, then x_1 is making tea. For all x_1, x_1 will not make tea. For all x_1, x_1 is an office clerk or x_1 is fast.
For all x_1, x_1 is not an office clerk can be inferred via the universal modus tollens rule.