Answer:
C. Conducting extra research
Explanation:
The group discussion technique that Han most clearly show in the above excerpt is "conducting extra research".
From the excerpt, we discover that Han said "I also found this article...". This reveals that he has an extra evidence aside the one he might have given or stated. The paper he brought out from his pocket was a research he made which he presented as an evidence to buttress his point.
So, what he showed is similar to conducting extra research.
