Answer:
3). No; she plagiarized her roommate's paper, pure and simple.
Explanation:
Ethics(in writing) is primarily concerned with the credibility and the character of the speaker. Ethical writing is characterized by the reliability that requires an appropriate description of the sources or material that are taken as a reference or incorporated in the text as evidence.
As per the given description, it is completely unethical as 'she plagiarized her roommate's paper, pure and simple' without even citing it. Ethically, she herself was supposed to be the sole creator of the paper and if any ideas or content is borrowed it requires to be cited or referred appropriately. Thus, option 3 is the answer.