1. The correct option is: Jasmine asked, "Do you think I should cut my hair to my chin, or only trim it?" (in direct speech, a comma must be used before a quotation and inverted commas are used at the beginning and the end of the sentence.
2. The correct option is: Nathan said, "I'm really sorry..."
3. The correct option would be: slow the action. All the other three options are valid reasons, since dialog moves the story forward by providing new information to the reader directly through the characters; it keeps the reader interested and through characters' words the reader can see characters' development.
4. The correct option would be: "She wants to go outside," Jesse said, "and walk the dog." If the direct speech is broken up by information about who is speaking, a comma (or a question mark or exclamation mark) is necessary to end the first piece of speech and a full stop or another comma before the second piece (before the inverted comma or commas).
5. Quotation marks are used around the speaker's actual words
6. In a narrative text or dialogue a comma indicates a break in the sentence (it could be when enumerating things, to indicate an apposition, a clause, etc.)
7. When creating dialogue each new speaker must have a beginning tagline.