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: If a zone undergoes dramatic changes in temperature with depth, it contains a thermocline. The tropical thermocline is typically deeper than the thermocline at higher latitudes. Polar waters, which receive relatively little solar energy, are not stratified by temperature and generally lack a thermocline because surface water at polar latitudes are nearly as cold as water at greater depths. Below the thermocline, water is very cold, ranging from 1 C to 3 C. Because this deep and cold layer contains the bulk of ocean water, the average temperature of the world ocean is 3.9 C.
Story: Keith was measuring the attributes of thermoclines. He selected two locations. One is near Miami, which is in the tropic. The other is near New York, which is in higher latitude. In total, he took four samples, sample A, sample B, sample C, and sample D. From Miami thermocline he took sample A. Then from below Miami thermocline he took sample B. From New York thermocline he took sample C. Finally, from below New York thermocline he took sample D.
Question: Which thermocline would be deeper, sample A or sample C?

A: sample A.
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Q: Background Paragraph: Cholesterol can't dissolve in the blood. It has to be transported to and from the cells by carriers called lipoproteins. Low-density lipoprotein, or LDL, is known as "bad" cholesterol. High-density lipoprotein (HDL) is known as good cholesterol. When too much LDL cholesterol circulates in the blood, it can slowly build up in the inner walls of the arteries that feed the heart and brain. Together with other substances, it can form plaque, and lead to atherosclerosis. If a clot forms and blocks a narrowed artery, a heart attack or stroke can result. Cholesterol comes from the food you eat as well as being made by the body. To lower bad cholesterol, a diet low in saturated fat and dietary cholesterol should be followed. Regular aerobic exercise also lowers LDL cholesterol and increases HDL cholesterol.
Story: Michael and Robert are two patients at a cardiology clinic. Both just received their blood test results and were told that they need to improve their cholesterol levels. They were each recommended to make changes to their diets. Michael took this advice to heart, and reduced the levels of saturated fat and dietary cholesterol he consumed. Robert, on the other hand, continued to consume high levels of saturated fat and dietary cholesterol.
Question: Who will have higher levels of LDL cholesterol in the future?

A: Robert.
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Q: Background Paragraph: Huge amounts of chemicals, such as fertilizers and pesticides, are applied to farm fields (see Figure below ). Some of the chemicals are picked up by rainwater. Runoff then carries the chemicals to nearby rivers or lakes. Dissolved fertilizer causes too much growth of water plants and algae. This can lead to dead zones where nothing can live in lakes and at the mouths of rivers. Some of the chemicals can infiltrate into groundwater. The contaminated water comes up in water wells. If people drink the polluted water, they may get sick.
Story: John studies how chemicals affect environment. He traveled to the Amish country to see their traditional ways of farming. He noticed they don't use any fertilizers or pesticides. He labeled this part of the study as case A. Then he visited a modern farming facility where they use tons of fertilizers and pesticides. He labeled this part of the study as case B.
Question: Which place would have less contamianted groundwater, case A or case B?

A:
case A.
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