Newspaper columnist: What caused the current recession is a hotly debated question.
Conclusion
It's a mistake to assume figuring out what caused the recession is essential to improving the economy.
Evidence (after all)
Corrective lenses were an effective treatment for myopia long before the cause was known to be genetic.
Evaluate
Whenever we do Main Conclusion, we read the paragraph differently, because we know that instead of putting the conclusion at the end of the paragraph (the most common place), on Main Conclusion and Role we expect the conclusion to be earlier than (at least some of) the supporting ideas.
Specifically, 90% of Main Conclusion questions have a conclusion that is - the First Sentence - a Rebuttal / Pivot idea
This one did the second. The first sentence is just a fact. There's no support provided to defend the idea that people are hotly debating what caused the current recession.
Then we see that magical however and think,
To clinch our suspicion that this 2nd sentence is the Conclusion, we want to see that it's being Supported. The fact that the 3rd sentence begins with one of the four Support Indicators (FABS = for, after all, because, since) tells us that the 2nd sentence was definitely the conclusion.
Goal
When we have Rebuttal style conclusions, we need to take an extra sec to state our author's position, using the wording of the position she's rebutting.
For example, if we hear, , then we need to say that the Conclusion is "Ketchup is not a vegetable".
So here the opposing position was that
Our author is saying
Let's find the answer that best matches the meaning of the 2nd sentence.