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: Fish mortality is a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock through death. The mortality can be divided into two types:

Natural mortality: the removal of fish from the stock due to causes not associated with fishing. Such causes can include disease, competition, cannibalism, old age, predation, pollution or any other natural factor that causes the death of fish. In fisheries models natural mortality is denoted by (M).[1]
Fishing mortality: the removal of fish from the stock due to fishing activities using any fishing gear.[1] It is denoted by (F) in fisheries models. 
Story: Bob works as a scientist for a large fishing company in Norway. Norway's government has strict regulations on fishing to protect its fish stock. Part of Bob's job is to provide the government with fish mortality data. Today, he has two samples of fish to investigate, sample A and sample B. Bob concluded sample A had natural mortality, but sample B had fishing mortality. 
Question: Would pollution be a casue of death or not a cause of death for sample B?
[EX A]: not a cause of death.

[EX Q]: Background Paragraph: As for the public health or food safety concern, organic foods are intended to be healthy, free of contaminations and free from agents that could cause human diseases. Organic milk is meant to have no chemical residues to consumers, and the restrictions on the use of antibiotics and chemicals in organic food production has the purpose to accomplish this goal. Although dairy cows in both organic and conventional farming practices can be exposed to pathogens, it has been shown that, because antibiotics are not permitted as a preventative measure in organic practices, there are far fewer antibiotic resistant pathogens on organic farms. This dramatically increases the efficacy of antibiotics when/if they are necessary. 
Story: Two farms were growing food for several nearby cities. Vole farm grew organic produce and produced organic milk, while Anthill farm did not possess the USDA organic certification. 
Question: Which farm produces more milk with no chemical residues?
[EX A]: Vole.

[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: Paul had a busy day storing XML. At 3 PM, he stored 22111 Gigabytes to the database. At 4 PM, he stored 33222 Gigabytes to the database. At 5 PM, he stored 44333 Gigabytes to the database. At 6 PM, he got dinner. At 7 PM, he stored 55444 Gigabytes to the database. At 8 PM, he stored 66555 Gigabytes to the database. At 9 PM, he went to sleep to finish storing XML tomorrow afternoon. 
Question: What time did storage costs go up:  4 PM or 6 PM?
[EX A]:
4 PM.