Final answer:
The best file type for saving word processing files is DOC.
Step-by-step explanation:
The best file type for saving word processing files is DOC.
DOC stands for Document and it is a file format used by Microsoft Word. It preserves the formatting, layout, and other elements of a document. It is widely supported by word processing software and can be easily edited and shared.
Other file types mentioned in the question, such as GIF, JPG, and MP3, are not suitable for saving word processing files. GIF and JPG are image file formats, while MP3 is an audio file format.