Respuesta :
I believe it's C, "They are not textbooks for the formal study of Buddhism, but introductions to its study." Hope that helps.
Answer: They are not textbooks for the formal study of Buddhism, but introductions to its study.
In this excerpt, the author is referring to a book about Buddhism. He wants to argue that the book is accessible to all people, not only to experts. The sentence that explains this more clearly is the last one. By saying that the books are introductions, not textbooks for formal study, the author reaches a wider audience. It shows readers that even if their interest in Buddhism is not academic, they can benefit from this book.