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: Leucism (/ˈluːsɪzəm, -kɪz-/)[1][2][3] is a condition in which there is partial loss of pigmentation in an animal resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle, but not the eyes.[3] It is occasionally spelled leukism. Unlike albinism, it is caused by a reduction in multiple types of pigment, not just melanin. 
Story: There is a strange phenomenon going on in Siberia. Biologist noticed that 60 percent of the Siberian Tigers have leucism, and another 40 percent have albinism. They labeled the first group as group A and the latter one as group B. They need to find the reasons for this phenomenon. 
Question: Which group would have multiple types of reduced pigment?

Ex Output:
group A.


Ex Input:
Background Paragraph: Mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases. With more surfaces exposed, there are more places for chemical weathering to occur ( Figure below ). Let’s say you wanted to make some hot chocolate on a cold day. It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have. Smaller pieces dissolve more easily. 
Story: Rocks commonly found in Beijing are often found spread out in smaller pieces, whereas rocks in Montreal typically remain large in size and don't break apart as much. Both Beijing and Montreal are expected to experience bouts of acid rain in the upcoming weeks. 
Question: Which area's rocks will have higher rates of chemical weathering caused by the acid rain?

Ex Output:
Beijing.


Ex Input:
Background Paragraph: Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. Its rate of loss has slowed with restrictions on pollutants, but it is still at risk. 
Story: Toronto is home to one of the leading manufacturers of aerosol sprays in the country. Because of this, homes in Toronto often spray high levels of aerosol on a regular basis. In Saskatchewan, meanwhile, the local government enacted a ban on aerosol sprays several years ago, so their level of aerosol use is now essentially zero. 
Question: Which city, Toronto or Saskatchewan, will be allowing higher levels of UV radiation to reach Earth?

Ex Output:

Toronto.