Many winemakers use cork stoppers; but cork stoppers can leak, crumble, or become moldy, so that those winemakers must often discard a significant proportion of their inventory of bottled wine. Bottlemaster plastic stoppers, which cannot leak, crumble, or mold, have long been available to winemakers, at a price slightly higher than that of traditional cork stoppers. Cork prices, however, are expected to rise dramatically in the near future. Clearly, therefore, winemakers who still use cork but wish to keep production costs from rising will be forced to reconsider plastic stoppers. And since the wine-buying public's association of plastic stoppers with poor-quality wine is weakening, there is an excellent chance that the Bottlemaster plastic stopper will gain an increased share of the marked for wine-bottle stoppers.

In the argument given, the two portions in boldface play which of the following roles?