Hereditary skill, local market for skill, introduction to new ideas and specialized suppliers are among the advantages that an industrial district can create for the firms that operate within the same industry. Rather than downsizing of subsidiaries, an industrial district can create growth of subsidiaries in that when firms are concentrated within a particular area, there will probably be new establishments in the form of subsidiaries; they will be the firms that supply materials or inputs to the industry. The correct answer is D.