In this task, you're given an article, a question which often contains a blank and four options (associated with "A", "B", "C", "D"). Your task is to find the correct answer (from the given options) for the question from the given article and return one of the options from "A", "B", "C", and "D". Do not generate anything else apart from one of the following characters: "A", "B", "C", "D". There is only one correct answer for each question.

Example Input: Article: Ruth Mckenney was born in 1911 in prefix = st1 /Mishawak,Indiana. She grew up inCleveand,Ohio, and at the age of fourteen she got her first job working nights in a printer's shop. She also worked as a waitress, but after dropping two fruits salads on the floor, she was fired. While Miss Mckenney was studying in a OhioStateUniversity, she found an outside job as a reporter for the Columbus Dispatch. In fact, she left college before she got her degree in order to devote all her time to newspaper work. She later worked on papers in Akron, Ohio, andNew York City. In New York, Miss Mckenney began to write stories about the amusing experiences she shared with her sisiter. These were published in theNew Yorkmagazine, and later in a book called "My Sister Eileen". This book was an immediate bestseller, and soon became a hit play. Miss Mckenney has also written a guide toEnglandand a number of serious books on American labor. Miss Mckenney married Richard Bransten in 1937. They had one daughter, and it came as no surprise when the author named her Eileen. Ruch Mckenney died in 1972.
Question: Ruth Mckenney started her newspaper work_.
Options: (A) after she left college (B) when she was a university student (C) before she got her degree (D) when she worked inNew York City
Example Output: B

Example Input: Article: Recent research has claimed that an excess of positive ions in the air can have an ill effect on people's physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is a rough balance between the positive and the negative charged. But sometimes this balance becomes disturbed and a larger proportion of positive ions are found. This happens naturally before thunderstorm, earthquakes when winds are blowing in certain countries. Or it can be caused by a build-up of static electricity indoors from carpets or clothing, or from TV sets, duplicators or computer display screens. When a large number of positive ions are present in the air many people experience unpleasant effects such as headaches, fatigue , excessive anger, and some particularly sensitive people feel sick or even suffer mental disturbance. Animals are also affected, particularly before earthquakes, snakes have been observed to come out, rats to flee from their burrows, dogs howl and cats jump about unaccountably. This has led the US Geographical Survey to fund a network of volunteers to watch animals in an effort to foresee such disasters before they hit vulnerable areas such as California. Conversely, when large numbers of negative ions are present, then people have a feeling of well-being. Natural conditions that produce these large amounts are near the sea, close to waterfalls or fountains, or in any place where water is sprayed, or forms a spray. This probably accounts for the beneficial effect of a holiday by the sea, or in the mountains with streams or waterfalls. To increase the supply of negative ions indoors, some scientists recommend the use of ionisers. They claim that ionisers not only clean and refresh the air but also improve the health of people sensitive to excess positive ions. Of course, there are the detractors, other scientists, who dismiss such claims and are skeptical about negative/positive ion research. Therefore people can only make up their own minds by observing the effects on themselves, or on others, of a negative rich or poor environment. After all it is debatable whether depending on seismic readings to anticipate earthquakes is more effective than watching the cat.
Question: What is an ion according to the passage?
Options: (A) It's a charged particle. (B) It's basically static electricity indoors. (C) It's a balance between the positive and negative charged. (D) It's an ill effect on people's physical and psychological health.
Example Output: A

Example Input: Article: For decades, public health officials have puzzled over a surprising fact about HIV: Only about 10-20 percent of infants who are breastfed by infected mothers catch the virus. Tests show, though, that HIV is indeed present in breast milk, so these children are exposed to the virus multiple times daily for the first several months of their lives. Now, a group of scientists and doctors from Duke University has figured out why these babies don't get infected. Human breast milk naturally contains a protein called Tenascin C that neutralizes HIV and, in most cases, prevents it from being passed from mother to child. Eventually, they say, the protein could potentially be valuable as an HIV-fighting tool for both infants and adults that are either HIV-positive or at risk of contracting the infection. The research, published in Proceedings of the National Academy of Sciences, was inspired by previous work by other researchers showing that, both in tissue cultures and live mice, breast milk from HIV-negativemothers was naturally endowed with HIV-fighting properties. Scientists suggested that a few different proteins in the milk could potentially be responsible, but no one knew which one. As part of the study, the researchers divided breast milk into smaller fractions made up of specific proteins via a number of filters -- separating the proteins by size, electrical charge and other characteristics--and tested which of these fractions, when added to a tissue culture, prevented the cells from being infected by HIV. Eventually, they found that one particular protein was present in all the HIV-resistant fractions but in none of the others: Tenascin C. Tenascin C works by blocking a key protein on HIV's envelope that normally ties up to a receptor on a T cell's membrane called CCR5. In doing so, Tenascin C prevents HIV from mixing with the T cell and injecting its RNA inside. Still, the researchers say that other natural elements in milk might play a role in fighting HIV as well. "It's clearly not the whole story, because we do have samples that have low amounts of this protein but still have HIV-neutralizing activity," the study's lead author Permar says. "So it may be acting in concert with other antiviral and antimicrobial factors in the milk." Whatever those other factors are, though, the finding vindicates (......) recent changes to UN guidelines that recommend even HIV-positive mothers in resource-poor countries should breastfeed, if they're taking anti-retroviral drugs to combat their own infection. The next steps, Permar says, are determining which area of Tenascin C is active and whether it can effectively prevent transmission in a live animal. If it works, it could potentially be incorporated into an HIV drug with broader applications. It's even possible that it could someday be adapted to reduce the risk of HIV transmission in adults as well as infants.
Question: Which of the following about Tenascin C is true?
Options: (A) It has become an effective tool in fighting HIV. (B) It was first found by Permar and her research group. (C) It can prevent transmission in a live animal effectively. (D) It can sometimes prevent mother-to-child transmission of HIV.
Example Output:
D