It depends:
- Sometimes a particular style is required or preferred by a particular discipline, but not always.
- Professors often have their own favorites.
- If they don't care, then feel free to choose your own, whether based on the discipline you are in or your own preferences.
Whatever style you use, make sure to use it consistently and accurately.. Using two or more guides in the same paper, or using a style improperly, is a good way to run into trouble.
Remember:
- Ask your professor which guide you should use.
- Use it consistently and accurately.