Answer:
The detail that best supports the idea that being interviewed at Ellis Island was very stressful for the immigrants is:
B. Some immigrants got so nervous that they couldn't answer the questions.
Step-by-step explanation:
The author made sure to give readers a taste of how stressful the interview was. That is why he included all those questions in the passage, as well as the detail about how flustered the immigrants felt. Imagine how tiring and enervating it is to travel all the way to a foreign country and, upon arriving, being interrogated in a manner that makes it clear you are being analyzed and judged. No wonder some of them were not able to answer the question, needing to get some time and rest before trying again.