C: Before Aisha could say something that she'd regret, she bit her mouth.
Explanation:
This sentence uses the idiom bite your tongue because Aisha wants not only to avoid speaking, but also saying something she would regret. The idiom bite your tongue means <em>to try hard to stop yourself from saying what you really think.</em>
The rest are things that you need to write down as you do your research: document the source title, the author, the web address, and also any important points that you might find.