The author claims that most studies of folktales told by Afro-American slaves are inadequate because the studies A. fail to recognize any possible Euro-American influence on the folktales B. do not pay enough attention to the features of a folktale that best reveal an African influence C. overestimate the number of folktales brought from Africa by the slaves D. do not consider the fact that a folktale can be changed as it is retold many times E. oversimplify the diverse and complex traditions of the slaves ancestral homeland