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 Input:
Background Paragraph: Gibberellins are hormones that cause the plant to grow. When gibberellins are applied to plants by scientists, the stems grow longer. Some gardeners or horticulture scientists add gibberellins to increase the growth of plants. Dwarf plants (small plants), on the other hand, have low levels of gibberellins ( Figure below ). Another function of gibberellins is to stop dormancy (resting time) of seeds and buds. Gibberellins signal that it’s time for a seed to germinate (sprout) or for a bud to open. 
Story: Keith has four plants in his backyard, plant A, plant B, plant C, and plant D. Plant A is very large, but plant B is smaller. Plant C and D are the same size. He applied some gibberellins to plant C, but didn't apply anything to plant D. He got curious about why some plants are bigger, while others are not. 
Question: Which plant would see increase in growth, plant C or plant D?

Ex Output:
plant C.


Ex Input:
Background Paragraph: A baby is born with zones of cartilage in its bones that allow growth of the bones. These areas, called growth plates , allow the bones to grow longer as the child grows. By the time the child reaches an age of about 18 to 25 years, all of the cartilage in the growth plate has been replaced by bone. This stops the bone from growing any longer. Even though bones stop growing in length in early adulthood, they can continue to increase in thickness throughout life. This thickening occurs in response to strain from increased muscle activity and from weight-lifting exercises. 
Story: Two brothers, Tom, aged 26, and Paul, aged 16, started weight-lifting to gain more muscle mass. Three years later they were 20-25 lbs. heavier. 
Question: Which brother had active growth cartilages?

Ex Output:
Paul.


Ex Input:
Background Paragraph: Thermoclines, or sudden changes in temperature. Where the air temperature is higher than the water temperature, shallow water may be warmed by the air and the sunlight but deeper water remains cold resulting in a lowering of temperature as the diver descends. This temperature change may be concentrated over a small vertical interval, when it is called a thermocline.[3][4]
Where cold, fresh water enters a warmer sea the fresh water may float over the denser saline water, so the temperature rises as the diver descends.[3]
In lakes exposed to geothermal activity, the temperature of the deeper water may be warmer than the surface water. This will usually lead to convection currents.[3]. 
Story: Deep lake presents geothermal activity, while Shallow lake has mixing of saline water with fresh water. Deep lake had more instances of divers having problems because of thermoclines. 
Question: Which lake has more water salinity?

Ex Output:

Shallow lake.