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: It is not cloudy. If Sarah plays squash, then it is cloudy. It is late if and only if Sarah is playing squash. If Karen were a janitor, then it is late. It is late if and only if Karen is a janitor.
Sarah is not playing squash can be inferred via the modus tollens rule. If it is late, then Sarah is playing squash can be inferred via the biconditional elimination rule. If it is late, then Karen is a janitor can be inferred via the biconditional elimination rule. If Sarah plays squash, then it is late can be inferred via the biconditional elimination rule. If Karen were a janitor, then it is late can be inferred via the biconditional elimination rule.