The last one with the word or
Answer: option (D).
Explanation: Nicholas fiddled with his thumbs, because, he didn’t dare look at his sister as she towered over him.
Commas are mostly used to divide or separate parts of a sentence in order to make the meaning clear and the sentence easier to read. Commas mark a brief pause in the sentence, usually at a point where you would naturally pause if you were speaking rather than writing.
