The answer to this is letter A. The home tab actually has a lot of buttons that you can use in order to make the document easier to navigate in and even personalize. This is the tab wherein you can find the font, font size, and font color.
You can also choose the type of structure for the paragraph which you think will work best depending on the type of document that you are creating. You can also control if you are going to place a title, headings, and subheadings. The home button will definitely help you create a lot of changes with the format of your document to make it look unique.