Why are headers and footers used in a document in Microsoft office?

Headers and footers are like margins but in addition allow for text such as titles and page numbers to be inserted in them. Every page in the document will have identically-sized tops and bottoms of pages, making for a satisfactory appearance.

However, the purpose is to structure the document coherently. In the options given all are correct, but the answer is really Option D, although not well worded. It is important that when printed the document reliably prints headers and footers on every page in the same way.