It seems that you understand why C is correct, but I will discuss it briefly. Then I will get to E.
The epic poem Sirat Bani Hilal has two characteristics. 1. It is the only Arabic epic poem still publicly performed. 2. Unlike most epic poems, it is sung rather than recited.
The author concludes that the "musical character of the performance" is the main reason why it is still performed today. The author assumes that one characteristic contributes to the other. He concludes that there is causation, when we only have a correlation. Just because they both exist, it doesn't mean they are directly related. This is a common flaw on the LSAT.
I'll make an example that is flawed according to answer choice E.
Premise: If my dog bites my neighbor (DBN), then I will be sued (S). DBN - - - - - - - - - - - - - -> S suf nec
Premise: I was sued. Conclusion: My dog bit my neighbor.
S - - - - - - - - - - - - > DBN
Do you see how this conclusion flipped our terms around? It takes the sufficient condition DBN and treats it like a necessary condition. I'll explain why this is not valid.
The necessary condition does not guarantee the sufficient condition. Just because I was sued, it does not necessarily mean that my dog bit my neighbor. Maybe my neighbor slipped on my driveway, or maybe I ran over his mailbox.
Answer choice E is just another way to state the flaw in believing that the necessary condition guarantees the sufficient condition. It doesn't. Although this is not the problem in the Arabic poem passage, this is another common one that you should be ready to recognize.