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 Michael plays squash, then Sarah is a janitor. It is overcast if and only if it is snowing. It is not overcast. Sarah is a janitor if and only if it is snowing.
If it is overcast, then it is snowing can be inferred via the biconditional elimination rule. If Sarah were a janitor, then it is snowing can be inferred via the biconditional elimination rule. If it snows, then it is overcast can be inferred via the biconditional elimination rule. If it snows, then Sarah is a janitor can be inferred via the biconditional elimination rule. It is not snowing can be inferred via the biconditional elimination rule.