How to answer this topic better
The score grows when you explain the effect of the book, not only the plot.
Say what the book was, when you read it, what it was about, and why it stayed with you.
You can record an answer, review the transcript, compare it with a stronger sample answer, and retry the same prompt without losing the main idea.
A book I enjoyed reading was The Alchemist by Paulo Coelho. I read it about two years ago when one of my friends recommended it to me. The story is quite simple, but I liked the message about following your goals and learning from your journey. What made it memorable for me was not only the plot, but the way it made me think about my own future. At that time, I was unsure about some personal decisions, and the book gave me motivation. That is why I still remember it as more than just an entertaining book.
This sounds like Band 6 because it includes a clear personal reaction, though the language and idea development are still moderate.