The author of the passage objects to many scholarly studies of African American history for which one of the following reasons? A. Their emphases have been on statutory law rather than on customary law. B. They have ignored specific historical situations and personages in favor of broad interpretations. C. They have focused on the least eventful periods in African American history. D. They have underemphasized the economic system that was the basis of the institution of slavery. E. They have failed to focus to a sufficient extent on the achievements of African Americans.