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: A large log placed in a fire will burn relatively slowly. If the same mass of wood were added to the fire in the form of small twigs, they would burn much more quickly. This is because the twigs provide a greater surface area than the log does. An increase in the surface area of a reactant increases the rate of a reaction. Surface area is larger when a given amount of a solid is present as smaller particles. A powdered reactant has a greater surface area than the same reactant as a solid chunk. In order to increase the surface area of a substance, it may be ground into smaller particles or dissolved into a liquid. In solution, the dissolved particles are separated from each other and will react more quickly with other reactants. 
Story: Two groups of scientists examined two fires. Group A put a large log on it, and group B made a fire with small twigs. They wanted to see which fire would last longer. 
Question: Which group had a fire that burned faster?

Ex Output:
group B.


Ex Input:
Background Paragraph: New species develop naturally through the process of natural selection . Due to natural selection, organisms with traits that better enable them to adapt to their environment will tend to survive and reproduce in greater numbers. Natural selection causes beneficial heritable traits to become more common in a population and unfavorable heritable traits to become less common. For example, a giraffe’s neck is beneficial because it allows the giraffe to reach leaves high in trees. Natural selection caused this beneficial trait to become more common than short necks. 
Story: Pam and Jill studied mammals. Jill was fascinated with their nutrition, while Pam was more interested and read about the natural selection phenomenon. 
Question: Which person studied more about organisms with traits that better enable them to adapt to their environment?

Ex Output:
Pam.


Ex Input:
Background Paragraph: Collision theory tells us that molecules need to collide in order for a reaction to take place. All else being equal, anything that increases the frequency of collisions would also increase the rate of reaction. One way to do this is to increase the concentrations of one or more of the reactants. Using a real world example, a busy freeway will experience much more frequent car collisions than a fairly empty neighborhood street. Similarly, forcing more randomly moving molecules into the same amount of space will cause an increased number of collisions over a given length of time, providing the reactants with more opportunities to transform into products. 
Story: John is a chemical engineer with a pharmaceutical company. He is trying to develop a drug that can be absorbed by the system in different rates. To that end, he conducted two experiments. In one case, he used lower concentrations of reactants, he called it case A. Then he used the same reactants in a higher concentration. He called it case B. 
Question: In which case the frequency of collisions would be lower, case A or case B?

Ex Output:

case A.