I actually read two of those books and it was the magician's nephew and the yearling. I liked the magician's nephew better than the yearling.
For one, it's best to remain honest even when no ones looking. Secondly, i'm sure the author of what ever it is would like to receive credit for the work they've done. It's just morally & ethically wrong to accept credit for something that's not original work.
I think it is D
Hope my answer help you?