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 overcast if and only if Karen is cooking. If it snows, then Karen is cooking. If it is overcast, then it is sunny. If it is sunny, then it is snowing.
If it is overcast, then it is snowing can be inferred via the transitivity rule. If it is sunny, then Karen is cooking can be inferred via the transitivity rule. If it is overcast, then Karen is cooking can be inferred via the biconditional elimination rule. If Karen cooks, then it is overcast can be inferred via the biconditional elimination rule.