You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.

[Q]: Background Paragraph: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy. 
Story: Marion county used coal and oil to produce electricity, while James county used nuclear energy for its electricity production. Both counties had a flourishing economy. 
Question: Which county caused more air pollution?
[A]: Marion.


[Q]: Background Paragraph: If all the other factors influencing humidity remain constant, at ground level the relative humidity rises as the temperature falls. This is because less vapor is needed to saturate the air, so vapor condenses as the temperature falls. In normal conditions, the dew point temperature will not be greater than the air temperature because relative humidity cannot exceed 100%.[4]. 
Story: Sam lived in Chicago for many years and experienced those high humidity days during the summer, the Indian summers in October and harsh and humid winters, so he decided to move to San Diego, in a warmer and much dryer climate. 
Question: Which city has less fog during summer?
[A]: San Diego.


[Q]: Background Paragraph: Hepatitis B is a disease of the liver. It is caused by a virus called hepatitis B, which can be passed through sexual activity. Hepatitis B causes vomiting. It also causes yellowing of the skin and eyes. The disease goes away on its own in some people. Other people are sick for the rest of their lives. In these people, the virus usually damages the liver. It may also lead to liver cancer. Medicines can help prevent liver damage in these people. There is also a vaccine to protect against hepatitis B. 
Story: Two friends ate lots of deviled eggs for Easter this year. Danny felt sick and went to the doctor where he found out he had been infected with hepatitis B. Paul was ok and didn't require medical attention. 
Question: Which friend didn't catch a disease of the liver?
[A]:
Paul.