The correct answer is: B. This is a good book.
The statement “This book can help because all good books help” is an example of a syllogism. A syllogism is a deductive argument in which a conclusion is drawn from two premises. In this case, the premises are:
- All good books help.
- This book is a good book.
The conclusion is:
- This book can help.
The conclusion follows logically from the premises, so it is valid. However, the premises may not be true, so the conclusion may not be true either. In this case, it is possible that the book is not actually a good book, or that it is not helpful even though it is a good book.
Option A is incorrect because it contradicts the premise that all good books help. Option C is incorrect because it contradicts the conclusion that this book can help. Option D is incorrect because it is a subset of option B.