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 Karen were a nurse, then Charles is a janitor. If Charles were a janitor, then it is raining. William is a bartender if and only if Karen is a nurse.
If Karen were a nurse, then it is raining can be inferred via the transitivity rule. If William were a bartender, then Karen is a nurse can be inferred via the biconditional elimination rule. If Karen were a nurse, then William is a bartender can be inferred via the biconditional elimination rule.