by maryadkins Wed Aug 24, 2011 2:34 pm
The quoted text appears in the middle of a discussion about how we can't look at a piece of old art from Africa and say, "This must be from X area because it's in a certain style." (Lines 14-15.) Rather, because of trade (line 12), styles spread. But, the author tells us, there are "centers of style"--the places where the art is made then dispersed widely. (C) captures this phenomenon--art produced in one spot then spreading outward.
(D) is not on point for a couple of reasons. First, these "centers" aren't described as "large geographical areas"--so we don't have a basis for concluding that. (Note that (C) just calls them "locations.") (D) also is wrong because line 20 tells us that the family in the "center of style" is of the same ethnicity. (D) says that there are different ethnic groups/tribes in the same center. And also, contrary to (D), the passage in this section isn't talking about how the objects are so similar, it's difficult for an outsider to distinguish them.
Let me know if this is still unclear!