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.

[EX Q]: Background Paragraph: Often, foreign exchange controls can result in the creation of black markets to exchange the weaker currency for stronger currencies. This leads to a situation where the exchange rate for the foreign currency is much higher than the rate set by the government, and therefore creates a shadow currency exchange market. As such, it is unclear whether governments have the ability to enact effective exchange controls.[1].
Story: On March 2015 Japans economy soared. There was a likelihood that the Japanese yen would rise in value. In the wake of this event, Japanese Government adjusted
the price of Japanese Currency Yen in accordance with the going market price. On the other hand, at he same time, UK was having economic downturn. There was a likelihood that the UK Currency Pound Sterling would go down. Fearing public backlash, UK Government kept the price of the Pound Sterling at the same level.
Question: Which Government took the wrong step to combat their currency being traded in the black market?
[EX A]: UK Government.

[EX Q]: Background Paragraph: In the U.S., the majority of electricity is produced by burning coal or other fossil fuels. This causes air pollution, acid rain, and global warming. Fossil fuels are also limited and may eventually run out. Like fossil fuels, radioactive elements are limited. In fact, they are relatively rare, so they could run out sooner rather than later. On the other hand, nuclear fission does not release air pollution or cause the other environmental problems associated with burning fossil fuels. This is the major advantage of using nuclear fission as a source of energy.
Story: Seattle produces a large amount of their electricity by burning fossil fuels due to the large presence of natural coal in the state. Jacksonville, on the other hand, has decreased their usage of fossil fuels used to produce electricity to low levels due to recent policy changes enacted by their state's government.
Question: Which city, Seattle or Jacksonville, will have less acid rain?
[EX A]: Jacksonville.

[EX Q]: Background Paragraph: If a solution has a higher concentration of hydronium ions than pure water, it has a pH lower than 7. A solution with a pH lower than 7 is called an acid . As the hydronium ion concentration increases, the pH value decreases. Therefore, the more acidic a solution is, the lower its pH value is. Did you ever taste vinegar? Like other acids, it tastes sour. Stronger acids can be harmful to organisms. For example, stomach acid would eat through the stomach if it were not lined with a layer of mucus. Strong acids can also damage materials, even hard materials such as glass.
Story: In his chemistry lab David is learning about acids. He took three solutions to identify them correctly, sample A, sample B, and sample C. Sample A is a strong acid; sample B is a weak acid; and sample C is not an acid. David needs to identify the content of each sample by learning about their attributes.
Question: Which sample would most likely damage materials, sample A or sample B?
[EX A]:
sample A.