Correct option is D
Footnotes in history writing primarily serve to indicate exact references, clarify additional information not elaborated in the main text, and provide the reader means to verify the author's claims through proper sourcing.
However, creating awareness about the writer’s approach and school of history is not typically the function of footnotes.
This is achieved through the main body of the work, especially in the introduction, preface, or methodology sections where the historian discusses their historiographical perspective.
Thus, while footnotes ensure transparency, source validation, and elaboration, they are not designed to explicitly showcase the writer's historiographical bias or approach.