In determining which sentence is punctuated correctly, it's essential to focus on the correct placement of commas and the structure of dialogue.
The sentence "One day I'll write a book', I said, 'not just a thriller, but a real book, about real people.'" is punctuated correctly for the following reasons:
- The quotation marks are placed at the beginning and end of the speaker's exact words, which is a standard convention for punctuating dialogue.
- Commas are used to separate the spoken parts from the attribution ("I said") and are placed inside the quotation marks.
- The internal structure of the sentence correctly punctuates the list with commas: "not just a thriller, but a real book, about real people."
Each element of the sentence adheres to conventional punctuation rules, ensuring clarity and correctness in conveying the dialogue and its meaning.