Doubt from Prepswift Justifying Answers video

[user3528]

Confused in this question:

I understand why (C) is the answer. But I had narrowed it to (C) and (E), and failed to eliminate (E) here- as this statement does appear to me as the main conclusion, i.e. gives us the actual potential origin of UHECRs.

Can you please guide me on the logic to elimintae (E) please, thanks!

[ganesh]

So the main conclusion of the passage would be something like this:

We don’t know where UHECRs come from, there are a couple of theories but each have issues.

The last sentence is a conclusion drawn to invalidate the second theory. It’s not the main conclusion.

[user3528]

Understood, thanks a lot!