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 not an office clerk, then William is a janitor. It is not raining. Karen is an office clerk if and only if it is raining.
If Karen were an office clerk, then it is raining can be inferred via the biconditional elimination rule. If it rains, then Karen is an office clerk can be inferred via the biconditional elimination rule. Karen is not an office clerk can be inferred via the biconditional elimination rule.