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: William is a nurse. Karen is a police officer or Charles is a mechanic. If it is cold, then William is not a nurse. Karen is a police officer if and only if it is cold.
It is not cold can be inferred via the modus tollens rule. If Karen were a police officer, then it is cold can be inferred via the biconditional elimination rule. If it is cold, then Karen is a police officer can be inferred via the biconditional elimination rule.