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: Barbara is a sailor or Charles is a soldier. If Barbara were a sailor, then Thomas is a server. If Charles were a soldier, then Thomas is a server. It is raining. If it is late, then it is not raining.
It is not late can be inferred via the modus tollens rule. Thomas is a server can be inferred via the disjunction elimination rule.