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 Mary were a doctor, then it is snowing. If it snows, then it is cold. For all z_4, if z_4 cooks, then z_4 is a doctor.
If Mary were a doctor, then it is cold can be inferred via the transitivity rule.