What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it snows, then Barbara is a police officer. If Barbara were a police officer, then it is snowing. Barbara is a police officer or it is not snowing.
If it snows, then Barbara is a police officer. It is snowing if and only if Barbara is a police officer. Barbara is a police officer if and only if it is snowing.