The correct answer is - both parties gain as a result of voluntary non-fraudulent exchange.
Trade is mutually beneficial for both sides, one side sells a product or raw material, thus making a profit out of it, the other side gets the product that it doesn't produces but needs it, or buys raw materials and makes its own product. So it is always the case that both sides benefit from the trade, where one of them makes a direct profit, and the other side gets what it requires for its needs.