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: About 10% of sedimentary rocks are limestones. The solubility of limestone in water and weak acid solutions leads to karst landscapes, in which water erodes the limestone over thousands to millions of years. Most cave systems are through limestone bedrock. 
Story: Bill is going on some trips this week. The first trip on Saturday is to Reginald's Peak. The next trip on Sunday is to Smuggler's Caves. He is very excited to see what both of the sites have to offer!. 
Question: On which day will Bill have a less likely chance to see limestone formations?
Example Output: Saturday.

Example Input: Background Paragraph: For comparison,  sunlight on Saturn is slightly brighter than Earth sunlight at the average sunset or sunrise (see daylight for comparison table). Even on Pluto, the sunlight would still be bright enough to almost match the average living room. To see sunlight as dim as full moonlight on Earth, a distance of about 500 AU (~69 light-hours) is needed; there are only a handful of objects in the Solar System known to orbit farther than such a distance, among them 90377 Sedna and (87269) 2000 OO67. 
Story: A startup has build a simple spaceship that uses only sunlight for its propulsion. The more sunlight it gets faster it moves. They planned to send the spaceship to three different points, point A, point B, and point C. Point A is near the planet Saturn, point B is near Pluto, and point C is about 69 light-hours away. 
Question: At which point the spaceship would move faster, point B or point C?
Example Output: point B.

Example Input: Background Paragraph: Compared to conventional milk production, organic milk production tends to have lower eutrophication potential per ton of milk or per hectare of farmland, because it potentially reduces leaching of nitrates (NO3−) and phosphates (PO4−) due to lower fertilizer application rates. Because organic milk production reduces pesticides utilization, it increases land use per ton of milk due to decreased crop yields per hectare. Mainly due to the lower level of concentrates given to cows in organic herds, organic dairy farms generally produce less milk per cow than conventional dairy farms. Because of the increased use of roughage and the, on-average, lower milk production level per cow, some research has connected organic milk production with increases in the emission of methane.Animal welfare issues vary among dairy farms and are not necessarily related to the way of producing milk (organically or conventionally). 
Story: Robert and his brother Dale are both dairy farmers that primarily produce milk products. Both Robert and Dale have farms that approximately the same size. Dale prefers to produce milk conventionally, as he likes the way that conventional milk tastes. Robert, on the other hand, decided to switch to organic milk production after reading an article online about it. 
Question: Whose farm, Robert's or Dale's, will use more land to produce the same amount of milk?
Example Output:
Robert's.