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.

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?
sample A.

Background Paragraph: Sometimes muscles and tendons get injured when a person starts doing an activity before they have warmed up properly. A warm up is a slow increase in the intensity of a physical activity that prepares muscles for an activity. Warming up increases the blood flow to the muscles and increases the heart rate. Warmed-up muscles and tendons are less likely to get injured. For example, before running or playing soccer, a person might jog slowly to warm muscles and increase their heart rate. Even elite athletes need to warm up ( Figure below ). 
Story: Two soccer players had a friendly match one on one after work. Paul had plenty of time to do his warm up properly, but John got there late and didn't warm up. Paul won the match. 
Question: Which player didn't have an increased hear rate before the match?
John.

Background Paragraph: While people have been able to prevent certain viral diseases by vaccinations for many hundreds of years, the development of antiviral drugs to treat viral diseases is a relatively recent development. Antiviral drugs are medications used specifically for treating the symptoms of viral infections. The first antiviral drug was interferon , a substance that is naturally produced by certain immune cells when an infection is detected. Over the past twenty years the development of antiretroviral drugs (also known as antiretroviral therapy, or ART) has increased rapidly. This has been driven by the AIDS epidemic. 
Story: Two brothers went on vacation. Tom partied heavily, and found out that he was infected with the HIV virus. Tim was more moderate, he went to the beach to get a sun tan, but he got an infection as well. Tim found out he got a bacterial infection and had to take antibiotics. 
Question: Which brother had to consider antiretroviral drugs?

Tom.