If we want to change the overall design of a word document, we shoulduse:a) themes b) page layoutc) watermark d) margins

To change the overall design of a Word document, the most suitable option would be:

Final Answer

a) themes

Explanation

Themes in Microsoft Word allow you to apply a consistent style throughout your document. A theme encompasses various elements, such as colors, fonts, and effects, that can dramatically change the visual appearance of your document with just a few clicks. By selecting a theme, all text can automatically adapt to the predefined font styles, and the color palette can change the background, headings, and other visual aspects, ensuring a cohesive look.

On the other hand, options like b) page layout primarily adjust how the document is structured, including margins and orientation but do not perform a complete design overhaul. c) watermark is used to insert a logo or text behind the document's content and does not significantly affect the overall design. d) margins allow you to control the blank space around the text on the page but are not intended for overall design changes. Thus, using themes is the most effective way to change the overall design quickly.