Hi, while both are plausible reasons that one would have written the sample in the second paragraph, we need to consider what evidence we have for each being the actual reason the author included it.
We have nothing to suggest that the author was writing it to convince comma specialists to do their research in that manor. In fact we don't even get a hint of that until the next paragraph.
However, we have direct support for D. The author notes that comms specialists see it as one culture overwhelming another. The example in the second paragraph is a direct counterexample Tom show this is not the case.