It can be inferred from the passage that the author believes which one of following about craft unions? A. Craft unions have been successful in ensuring that the wages of their members remain higher than the wages of nonunion workers in the same occupational groups. B. The number of minority workers joining craft unions has increased sharply in states that have not adopted right-to-work legislation. C. Wages for workers belonging to craft unions have generally risen faster and more steadily than wages for workers belonging to industrial unions. D. The wages of workers belonging to craft unions have not been significantly affected by right-to-work legislation, although the wages of workers belonging to industrial unions have been negatively affected. E. The wages of workers belonging to craft unions are more likely to be driven up in the event of labor shortages than are the wages of workers belonging to industrial unions.