Based on the passage, which one of the following, if true, would have been most relevant to the project Porter was working on at the time of his death? A. African-American crafts of the eighteenth and nineteenth centuries have certain resemblances to European folk crafts of earlier periods. B. The paintings of some twentieth-century European artists prefigured certain stylistic developments in North African graphic art. C. The designs of many of the quilts made by African-American women in the nineteenth century reflect designs of European trade goods. D. After the movement of large numbers of African-Americans to cities, the African influences in the work of many African-American painters increased. E. Several portraits by certain twentieth-century European painters were modeled after examples of Central African ceremonial masks.