Concept:Structural unemployment occurs when the composition of aggregate demand changes, making existing worker skills outdated for the new job pattern.Explanation:Changes in the pattern of aggregate demand mean consumers now spend more in some sectors and less in others. As demand falls, some industries lay off workers. Those workers may not have the skills needed in the expanding industries. This skill mismatch creates structural unemployment. Seasonal unemployment comes from regular yearly fluctuations, while frictional unemployment is the short-term movement between jobs. Therefore, the correct type is structural unemployment.Answer:B. Structural unemployment.