What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? John is not playing a game or it is snowing. John is playing a game or Barbara is driving a car. If Charles writes a letter, then it is not snowing. For all y_2, y_2 will not drive a car.
Barbara is driving a car or it is snowing. If Barbara were a writer, then John is playing a game.