Final answer:
To summarize correctly, the main idea to include should focus on the shared memories and the duality within a single person's nature, as seen in Jekyll and Hyde, reflecting broader human experiences.
Step-by-step explanation:
The student's question appears to relate to an excerpt that is not provided, but the correct main idea to include in a summary based on the provided references and common literary themes might be: Jekyll and Hyde shared memories as different facets of the same person, grappling with the duality of human nature. The student's choice of summary should focus on the connection between characters' actions and feelings and how they represent unique yet universal human experiences. For instance, the complexities of characters in Fitzgerald's work, as well as the depth of personal growth in London's The Call of the Wild, highlight the essence of individual experiences that may resonate broadly, because they stem from common human conflicts and emotions.