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: Although some lipids in the diet are essential, excess dietary lipids can be harmful. Because lipids are very high in energy, eating too many may lead to unhealthy weight gain. A high-fat diet may also increase lipid levels in the blood. This, in turn, can increase the risk for health problems such as cardiovascular disease. The dietary lipids of most concern are saturated fatty acids, trans fats, and cholesterol. For example, cholesterol is the lipid mainly responsible for narrowing arteries and causing the disease atherosclerosis. 
Story: Ben and Jerry were two friends with very different dietary habits. Jerry ate healthy food, and was always on top of his caloric consumption, while Ben overate because he loved fatty foods such as butter, bacon et al. 
Question: Which friend had a lower blood lipid level?
[A]: Jerry.


[Q]: Background Paragraph: Air pollution is harmful to human beings and other living things. About 22 million people die from air pollution each year. Breathing polluted air increases the risk of developing lung diseases such as asthma and lung cancer. Breathing bad air also increases the chances of dying from other diseases. Children are most likely to be affected by air pollution. That’s because their lungs are still developing and growing. Children also take in more air for their size than adults do. Some air pollutants damage the environment as well as the health of living things. The type of damage depends on the pollutant. Air pollution can also harm the environment. 
Story: Michael and Thomas are brothers whose careers have taken them to different cities. Michael lives in Beijing, where the levels of air pollution are fairly high due to the extensive manufacturing industry. Thomas, on the other hand, lives in Seattle, which has low levels of air pollution thanks to government initiatives and culture attitudes in the region. 
Question: Who has a higher risk of developing asthma?
[A]: Michael.


[Q]: Background Paragraph: Electromagnetic radiation is energy that travels in waves across space as well as through matter. Most of the electromagnetic radiation on Earth comes from the sun. Like other waves, electromagnetic waves are characterized by certain wavelengths and wave frequencies. Wavelength is the distance between two corresponding points on adjacent waves. Wave frequency is the number of waves that pass a fixed point in a given amount of time. Electromagnetic waves with shorter wavelengths have higher frequencies and more energy. 
Story: David is experimenting with electromagnetic waves. He has four different waves to study, wave A, wave B, wave C, and wave D. In wave A, distance between two corresponding points on adjacent waves is greater than that of wave B.
In wave C, the number of waves that pass a fixed point in a given time is greater than that of wave D. 
Question: Which wave has lower frequency, wave A or wave B?
[A]:
wave A.