According to the "Northern Song Dynasty regime" and "Southern Song Dynasty regime" in the picture, it can be judged that this reflects the Song Dynasty. Then, according to the picture, Jiangnan has become the main economic zone, which shows the theme of economic development in the South and the gradual shift of economic focus to the South in the Song Dynasty. Item D is correct; The flourishing age of Kaiyuan appeared in the early years of Xuanzong in Tang Dynasty, excluding Item A; The title reflects the economic development of the Song Dynasty, but it does not reflect the coexistence of ethnic regimes or the policy of valuing literature over martial arts, excluding BC. So choose item D.