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.
--------
Question: Background Paragraph: Storing large volumes of data – When storing XML to either file or database, the volume of data a system produces can often exceed reasonable limits, with a number of detriments: the access times go up as more data is read, CPU load goes up as XML data takes more power to process, and storage costs go up. By storing XML data in Fast Infoset format, data volume may be reduced by as much as 80 percent. 
Story: Carl had a busy day storing XML. At 1 PM, he stored 1000 Gigabytes to the database. At 2 PM, he stored 2000 Gigabytes to the database. At 3 PM, he stored 3000 Gigabytes to the database. At 4 PM, he got dinner. At 5 PM, he stored 4000 Gigabytes to the database. At 6 PM, he stored 5000 Gigabytes to the database. At 7 PM, he went to sleep to finish storing XML tomorrow. 
Question: What time did storage costs go up:  3 PM or 7 PM?

Answer: 3 PM.


Question: Background Paragraph: You generally can’t see, smell, taste, hear, or feel radiation. Fortunately, there are devices such as Geiger counters that can detect radiation. A Geiger counter, like the one pictured in the Figure below , contains atoms of a gas that is ionized if it encounters radiation. When this happens, the gas atoms change to ions that can carry an electric current. The current causes the Geiger counter to click. The faster the clicks occur, the higher the level of radiation. You can see a video about the Geiger counter and how it was invented at the URL below. 
Story: Keith landed a job with the EPA. As part of his training he needed to learn how the Geiger counter works. To learn more about the counter he tested it in three different locations, location A, location B, and location C. Location A had very high radiation; location B had low radiation; and location C didn't have any radiation. Keith learned how the counter works in locations with varying degrees of radiation. 
Question: Which location would have slower clicks, location A or location B?

Answer: location B.


Question: Background Paragraph: If only 1.0 mL of 0.10 M hydrochloric acid is added to 1.0 L of pure water the pH drops drastically from 7.0 to 4.0. This is a 1000-fold increase in the acidity of the solution. For many purposes, it is desirable to have a solution which is capable of resisting such large changes in pH when relatively small amounts of acid or base are added to them. Such a solution is called a buffer. A buffer is a solution of a weak acid or a base and its salt. Both components must be present for the system to act as a buffer to resist changes in pH. Commercial buffer solutions, which have a wide variety of pH values, can be obtained. 
Story: John is a scientist in a large pharmaceutical company. He devices many useful products using his knowledge of chemistry. Today, he has four solutions in front of him, solution A, solution B, solution C, and solution D. Solution A is a buffer, but solution B is not a buffer. Solution C is acidic, but solution D is not acidic. He needs to figure out what each solution does. 
Question: Which solution may assist in changes in pH, solution A or solution B?

Answer:
solution B.