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.

[EX Q]: Background Paragraph: It mutates DNA. The Chernobyl disaster was a nuclear accident that occurred on April 26, 1986. It is considered the worst nuclear power plant accident in history. A Russian publication concludes that 985,000 excess cancers occurred between 1986 and 2004 as a result of radioactive contamination. The 2011 report of the European Committee on Radiation Risk calculates a total of 1.4 million excess cancers occurred as a result of this contamination. 
Story: In Arizona, there are two cities approximately 300 miles apart. Both of them have nuclear power plants in their town. Blinkton had a catastrophic meltdown at their nuclear power plant approximately 15 years ago. The city, Frafton, has a nearly identical nuclear power plant but has never experienced a nuclear accident before. 
Question: Which city will have fewer people with cancer?
[EX A]: Frafton.

[EX Q]: Background Paragraph: Storing large volumes of data – When storing XML to either file or database, the volume of data a system produces can often exceed reasonable limits, with a number of detriments: the access times go up as more data is read, CPU load goes up as XML data takes more power to process, and storage costs go up. By storing XML data in Fast Infoset format, data volume may be reduced by as much as 80 percent. 
Story: Gary had a lot of storing to do on his computer. At 1 PM, he stored 1 Gigabyte of XML data to the main file. At 2 PM, he stored 2 Gigabytes of XML data to the main file. At 3 PM, he didn't store anything. At 4 PM, he stored 3 Gigabytes of XML data to the main file. At 5 PM, he stored 4 Gigabytes of XML data to the main file. At 6 PM, he did nothing. At 7 PM, he got dinner. At 8 PM, he stored 5 Gigabytes of XML data to the main file. He went to sleep at 9 PM and had to start again in the morning. 
Question: What hour did storage costs go up: 2 PM or 6 PM?
[EX A]: 2 PM.

[EX Q]: Background Paragraph: About 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. 
Story: Greg has been on a rock finding kick. Lately, he has decided he wanted to explore areas with higher amounts of limestone. He only has time this year for one trip, and his options are limited. He can go to Mount St. Helens, or he can go to the Meremac Caverns. 
Question: Where should Greg go to have a higher chance of finding limestone?
[EX A]:
Meremac Caverns.