What is the difference between an authors purpose and his or her central ideas?

A. Authors purpose is the authors main idea; Central ideas are readers’ responses to the text .

B. Authors purpose is the authors reason for writing; Central ideas or insights the author wants to convey.

C. All authors purpose are the types of information as the other conveys; Central ideas or the other is bias or prejudice.

D. Authors purpose is the author in preparation for writing; Central ideas are the others attitudes towards the subject;