C. They tell stories in rhythms that were easy to remember.
Ancient poetry was not written down. It was used as a way for traveling storytellers to remember their stories. Think of great epics such as the Illiad and the Odyssey. These stories are not deeply personal, nor do they abandon structure. They tell stories about the Trojans and Spartans. Also, choosing A would be an incorrect choice because throughout history most people were unable to read.