I am curious as to why A is not correct. The Reason I did not pick D was because it only mentions the controversy. I felt the passage also went into a good explanation of the benefits/possible uses which is why I discarded D (as a correct but not capturing the full scope of the passage kind of answer) and selected A
I too had this thought process.
How can you differentiate between what is the main point vs the primary purpose of a given passage? Wouldn't both a main point and a primary purpose question be searching for the why?
In addition the thought process above, I also noted that the author spent 2 paragraphs describing the process of rDNA, 2 paragraphs presenting its potential benefits, and two paragraphs discussing the potential risks. As such, why is it that primary purpose is summarizing the controversy (answer D) vs answer A that encompasses the whole passage?
Thanks in advance!