instruction:
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: Hemophilia is the name of a group of hereditary diseases that affect the body's ability to control blood clotting. Hemophilia is caused by a lack of clotting factors in the blood. Clotting factors are normally released by platelets. Since people with hemophilia cannot produce clots, any cut can put a person at risk of bleeding to death. The risk of internal bleeding is also increased in hemophilia, especially into muscles and joints. This disease affected the royal families of Europe. 
Story: Two women go into a doctor's office for a routine physical. As is usual for a physical, the doctor takes a blood sample from both women to analyze for any issues. Upon looking at the blood, the doctor notices that Jan's platelet count is low, but other than that her blood is fine. Marcia's platelet count is not low and she has no other issues. 
Question: Which woman will struggle creating blood clots?
answer:
Jan.


question:
Background Paragraph: The mechanical advantage of a machine is the factor by which it changes the force applied to the machine. Many machines increase the force applied to them, and this is how they make work easier. Compound machines tend to have a greater mechanical advantage than simple machines. That’s because the mechanical advantage of a compound machine equals the product of the mechanical advantages of all its component simple machines. The greater the number of simple machines it contains, the greater its mechanical advantage tends to be. 
Story: David was studying the processes involved in a machine. He collected a simple machine. He tagged it as case A. To compare it with compound machines, he collected two compound machines, case B and case C. Case B is a compound machine with few simple machines. And, case C is a compound machine with many simple machines. 
Question: Would case C have greater or smaller mechanical advantage than case B?
answer:
greater.


question:
Background Paragraph: A comet tail—and coma—are features visible in comets when they are illuminated by the Sun and may become visible from Earth when a comet passes through the inner Solar System. As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them. Separate tails are formed of dust and gases, becoming visible through different phenomena; the dust reflects sunlight directly and the gases glow from ionisation. Most comets are too faint to be visible without the aid of a telescope, but a few each decade become bright enough to be visible to the naked eye. 
Story: Stargazers across the world wait for 2020 when newly discovered very bright Neil's comet would start to pass through the inner solar system On December 21, 2020. After December 27, 2020 the comet would leave the inner solar system. Like many other enthusiasts Ken bought a telescope for the event. His friend Mike is interested in that event too, but is too busy to buy a telescope. 
Question: On which date Neil's Comet would not be visible, December 21, 2020 or December 27, 2020?
answer:

December 27, 2020.