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.

Example Input: Background Paragraph: Parallel slowdown is a phenomenon in parallel computing where parallelization of a parallel algorithm beyond a certain point causes the program to run slower (take more time to run to completion).[1]

Parallel slowdown is typically the result of a communications bottleneck. As more processor nodes are added, each processing node spends progressively more time doing communication than useful processing. At some point, the communications overhead created by adding another processing node surpasses the increased processing power that node provides, and parallel slowdown occurs. 
Story: John landed a job as an IT manager. His boss asked him to figure out problems in two similar programs, program A and program B. John found program A having parallel slowdown, but program B does not have parallel slowdown. He has to weigh the merits of using these programs. 
Question: Which program is doing less useful processing, program A or program B?
Example Output: program A.

Example Input: Background Paragraph: Human beings invented agriculture about 10,000 years ago. This provided a bigger, more dependable food supply. It also allowed people to settle down in villages and cities for the first time. Birth rates went up because there was more food and settled life had other advantages. Death rates also rose because of crowded living conditions and diseases that spread from domestic animals. Because the higher birth rates were matched by higher death rates, the human population continued to grow very slowly. 
Story: David was studying human history. He selected two specific eras of human history, era A and era B. Era A was before humans had invented agriculture. And, era B was after the invention of agriculture. He noticed that human societies had changed dramatically after the invention of agriculture. 
Question: Did era A have higher or lower brith rate than era B?
Example Output: lower.

Example Input: Background Paragraph: Carbon monoxide is used in modified atmosphere packaging systems in the US, mainly with fresh meat products such as beef, pork, and fish to keep them looking fresh. The carbon monoxide combines with myoglobin to form carboxymyoglobin, a bright-cherry-red pigment. Carboxymyoglobin is more stable than the oxygenated form of myoglobin, oxymyoglobin, which can become oxidized to the brown pigment metmyoglobin. This stable red color can persist much longer than in normally packaged meat. Typical levels of carbon monoxide used in the facilities that use this process are between 0.4% to 0.5%. 
Story: Anna is going grocery shopping today. She gets to the meat section and decides to buy some ground beef. While looking at the cases she notices 2 brands of meat, Brand A and brand B. Bother were packaged the same day but package B's meat is noticeably more brown in color. 
Question: Which package of meat was likely treated with carbon monoxide, package A or package B?
Example Output:
A.