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: If Sarah works, then it is overcast. Elisabeth is a cashier or it is not overcast. Sarah is not working. If Elisabeth were a cashier, then Sarah is working.
Elisabeth is not a cashier can be inferred via the modus tollens rule. If Elisabeth were a cashier, then it is overcast can be inferred via the transitivity rule. If it is overcast, then Elisabeth is a cashier can be inferred via the rewriting rule.