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: A large log placed in a fire will burn relatively slowly. If the same mass of wood were added to the fire in the form of small twigs, they would burn much more quickly. This is because the twigs provide a greater surface area than the log does. An increase in the surface area of a reactant increases the rate of a reaction. Surface area is larger when a given amount of a solid is present as smaller particles. A powdered reactant has a greater surface area than the same reactant as a solid chunk. In order to increase the surface area of a substance, it may be ground into smaller particles or dissolved into a liquid. In solution, the dissolved particles are separated from each other and will react more quickly with other reactants. 
Story: Two groups of scientists examined two fires. Group A put a large log on it, and group B made a fire with small twigs. They wanted to see which fire would last longer. 
Question: Which group had a fire that burned faster?
[A]: group B.


[Q]: Background Paragraph: Noble gases are also used to fill the glass tubes of lighted signs like the one in the Figure below . Although noble gases are chemically nonreactive, their electrons can be energized by sending an electric current through them. When this happens, the electrons jump to a higher energy level. When the electrons return to their original energy level, they give off energy as light. Different noble gases give off light of different colors. Neon gives off reddish-orange light, like the word “Open” in the sign below. Krypton gives off violet light and xenon gives off blue light. 
Story: Bob owns a store that sells signs. He has a large selection of different signs that are for sale, and they come in all sorts of different colors. His closed sign is a reddish-orange. His open sign is a violet color, and his sale sign is blue. 
Question: Which sign in Bob's store uses Neon gas?
[A]: closed sign.


[Q]: Background Paragraph: Cavitation is, in many cases, an undesirable occurrence. In devices such as propellers and pumps, cavitation causes a great deal of noise, damage to components, vibrations, and a loss of efficiency. Cavitation has also become a concern in the renewable energy sector as it may occur on the blade surface of tidal stream turbines.When the cavitation bubbles collapse, they force energetic liquid into very small volumes, thereby creating spots of high temperature and emitting shock waves, the latter of which are a source of noise. The noise created by cavitation is a particular problem for military submarines, as it increases the chances of being detected by passive sonar. 
Story: Stephanie and Barb are two friends that belong to a sailing club. They are having a lunch at the cafe in the club and discussing their latest boat purchases. Stephanie mentions that her latest boat she has been using has cavitation. Barb takes a bite of her sandwich and remarks that the boat she is currently using doesn't have any cavitation. 
Question: Whose boat will be unable to be heard from farther away?
[A]:
Barb.