We know that the Chinese porcelain dates back to 16th century and it was placed in its final location when that location was still populated.
Most importantly, it was first of its kind. Keeping this in mind, let’s sort out the choices:
(A) The former inhabitants of Great Zimbabwe most likely learned to make glassware in the style of artisans from other areas of the world.
The key information that probably brings us to the correct choice is about the Chinese porcelain that is not glassware. The only glassware mentioned in the passage in Arabian glass. Yes, there is possibility that local artisans learned how to make such glass at home, but it may well be brought to Zimbabwe from Arabian countries. So incorrect.
(B) The local pottery was not blue and white porcelain.
We have been told that Chinese dish was white and blue, but can’t ascertain whether local produce wasn’t in such colors. This choice leads to think that the origin of Chinese dish was determined by the color of its fragments. However, there can be other signs, such as Chinese writing “made in China” or whatever, on the fragments. In this case, local pottery may well have been in white or blue.
(C) The site was one at which extensive trading occurred.
The fact that there are multiple foreign artifacts in one region doesn’t necessarily prove that they were traded. It can be true that local people simply collected such items when they traveled to foreign countries.
(D) Scholarly consensus that the site was abandoned in 1450 should be reevaluated.
Correct choice because we know that the Chinese dish is one of its kind and thus can’t be produced by local artisans well before 1450. It was probably brought here from somewhere by local people. Chinese people couldn’t populate this site once local people moved out, because in such case the number of such Chinese dished would high. So, there is probability that local people still lived here around 16th century and thus choice D is correct.
(E) Further excavations will likely yield artifacts from different areas than those already identified.
This choice is really uncalled for because nothing in the passage talks about what would happen in the future excavations.
So D