The Answer is C writing or speech that is written by someone high of social standing
It is important because a narrative is supposed to tell you about all the important parts of a story so without the key events it wouldn't be a complete narrative.
Jack believes that they no longer need the conch because they know who to listen to and who to allow to speak. They no longer need to conch to decide that. This shows regression because they learned to effectively choose someone to speak without needing the conch to do it for them.
The writing style for sure since there wouldn't be a writing style anymore. A large part of the meaning behind epic poetry is the style it's written in which conveys a lot of emotion behind the story.