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: 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?
[EX A]: sample A.

[EX Q]: Background Paragraph: There was no additional air in the tire the second time Lawrence checked the air pressure, but something did change between the two measurements. The tires had rolled over 10 miles of road on the trip to school. Any time one surface moves over another, it causes friction. Friction is a force that opposes the motion of two surfaces that are touching, and friction between two surfaces always generates heat. Quickly rub your hands together and you'll feel the heat generated by the friction between them. As the tires moved over the road, friction between the tires and road generated heat. In short, the tires got warmer and so did the air inside them.
Story: There was a carnival game at the fair that allowed you to win a basketball if you could correctly guess which of the two balls had spun around a circular track more times. Each ball would be dropped into identical circular tracks and then a curtain would cover them. Ball A would then spin around the track a certain amount of times, and Ball B would spin around a certain amount of times. After they were done spinning, you had to guess which ball completed more revolutions. A boy came up and had no idea how to figure out the answer, but when he picked them up he noticed that Ball A was slightly warmer than Ball B.
Question: Which ball completed more revolutions?
[EX A]: Ball A.

[EX Q]: Background Paragraph: Soil formation, or pedogenesis, is the combined effect of physical, chemical, biological and anthropogenic processes working on soil parent material. Soil is said to be formed when organic matter has accumulated and colloids are washed downward, leaving deposits of clay, humus, iron oxide, carbonate, and gypsum, producing a distinct layer called the B horizon. This is a somewhat arbitrary definition as mixtures of sand, silt, clay and humus will support biological and agricultural activity before that time. These constituents are moved from one level to another by water and animal activity. As a result, layers (horizons) form in the soil profile. The alteration and movement of materials within a soil causes the formation of distinctive soil horizons. However, more recent definitions of soil embrace soils without any organic matter, such as those regoliths that formed on Mars and analogous conditions in planet Earth deserts.An example of the development of a soil would begin with the weathering of lava flow bedrock, which would produce the purely mineral-based parent material from which the soil texture forms. Soil development would proceed most rapidly from bare rock of recent flows in a warm climate, under heavy and frequent rainfall. Under such conditions, plants (in a first stage nitrogen-fixing lichens and cyanobacteria then epilithic higher plants) become established very quickly on basaltic lava, even though there is very little organic material. The plants are supported by the porous rock as it is filled with nutrient-bearing water that carries minerals dissolved from the rocks. Crevasses and pockets, local topography of the rocks, would hold fine materials and harbour plant roots. The developing plant roots are associated with mineral-weathering mycorrhizal fungi that assist in breaking up the porous lava, and by these means organic matter and a finer mineral soil accumulate with time. Such initial stages of soil development have been described on volcanoes, inselbergs, and glacial moraines.
Story: Ben and Jerry studied agricultural sciences. Ben was specialized in pedology and pedogenesis, while Jerry specialized in entomology and phytopathology.
Question: Which person learned more about soil formation?
[EX A]:
Ben.