A conceptual model is to represent the authors and subject classifications of books. There are no functional dependencies between the identifiers of the entity types Author, Book, Subject, but an...

A conceptual model is to represent the authors and subject classifications of books. There are no functional dependencies between the identifiers of the entity types Author, Book, Subject, but an author is always associated with all the subject classifications applicable to a book he or she has written.

Assess the merits of each of the following structures. Which structure would you recommend, and why?