In economics, a "Veblen good" is an item which people buy in greater quantity when the price goes up. According to the Law of Supply and Demand, when the price of an ordinary item goes up, demand drops, i.e. people buy fewer of them. A Veblen good is a luxury item to which status is attached, such as a designer outfit or luxury car. As the price of such an item increases, its prestige increases, which makes the item that much more desirable.Therefore, as the price increases, the demand also increases, and more of these items are sold.In the argument, the two portions in boldface play which of the following roles?
【选项】The first is a prediction; the second gives evidence for this prediction.