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: Robert is not an electrician. If Robert were an electrician, then Sarah is a carpenter. If Sarah were a carpenter, then Robert is an electrician. For all x_10, x_10 is a carpenter or x_10 is curious.
Sarah is not a carpenter can be inferred via the modus tollens rule.