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.

Ex Input:
Article: In many romantic movies or TV shows one scene always appears. It involves a handsome man standing outside a young woman's window, singing a love song to her to win her over. However, trying to woo a female with songs is not just something that humans do. A few animals sing love songs as well. Birds and elephants are romantic but the latest animal to _ a female might surprise you--it is the humble mouse. You may find it odd to find out that mice sing. We do not hear them because the frequency of their voice is so high. In fact, scientists have known for some time that male mice make special sounds to females, but it has always been assumed that the sounds are produced instinctively and randomly, with little thought going into the process. But new research suggests otherwise. When male mice with different voices were put in a cage together, scientists found that they would gradually change their pitches to sound like one another. But when a female mouse was put in the cage with two males, one male would change his pitch to match the other. "It was usually the smaller animal changing the pitch to match the larger animal," professor Erich Jarvis, leader of the study, from Duke University, US, told BBC News. This ability, known as vocal learning, is rare in the natural world. It had been thought to be limited to some birds, such as parrots--as well as whales and dolphins. The latest findings challenge the long-held opinion that mice cannot learn to adapt their voices. Scientists also found the part of the brain that controls the mice's singing ability. In the experiment, they damaged the cells in this part of the mice's brain and found that the animals couldn't keep their songs in pitch or repeat them any more. This also happened when the mice became deaf. Jarvis said that this finding had changed his understanding of the way mice make sound. "In mice we find that the pathways that are at least modulating these vocalizations are in the forebrain, in places where you actually find them in humans," he said. "If we're not wrong, these findings will be a big boost to scientists studying diseases like autism and anxiety disorders."
Question: Which of the following is proven wrong by the latest discovery?
Options: (A) The frequency of mice's voice is so high that it's impossible for humans to hear it. (B) When male mice make special sounds to females they can't control the sounds. (C) Birds and elephants are both romantic animals that are good at expressing love. (D) Animals like mice are smart even though they often make sounds randomly.

Ex Output:
B

Ex Input:
Article: During the 1800s, African Americans worked long days in the fields of the American South.To ease their labor, they sang "field hollers" that they had brought from Africa.One person sang a line.Then a group of workers repeated it.The songs' words told of the hardships that people suffered.African Americans sang "shout spirituals", or joyous religious songs.They clapped their hands and stomped their feet to the music. After the Civil War, the music changed dramatically.African American music, from ballads to church music, took new forms.It also adapted dance music, called "jump-ups".which had great rhythm. Banjos became popular.A blues singer usually played a call and response with the banjo.By the early 1900s, the guitar had replaced the banjo as the main blues instrument. Northern Mississippi - called the Delta - was the center of the blues tradition.By the 1920s, the Delta had many clubs, so-called juke joints.African Americans listened and danced to music in these clubs.Some of the greatest blues men and women performed there. Blues have a soulful sound that is easy to recognize.The musical notes are often "bent".That is, they are changed slightly to give a song more strength.Whatever their origin, these bent notes most often define the blues. Lyrics are the words of a song.Blues lyrics describe everyday life.The lyrics, often about relationships between men and women, are often very intense and personal.They tell about sorrow and overwork.They tell about finding or losing love, having money or being broke, being happy or sad and lonely.The lyrics may use humor to describe life's trials and joys.They almost always use the rhythms of everyday speech.A typical blues stanza, or group of lyrics, has three lines.The second line repeats the first line.The third line has different words. By the 1940s, large numbers of African Americans had left the Delta and moved north to work. Many settled in Chicago.There, a new kind of "electric", or "Chicago" blues began.Many of its themes were the same, but these blues had "wailing" electric guitars and harmonicas.The music had a steady, strong drumbeat.The loud, driving Chicago blues was excellent dance music.Chicago blues led to the birth of a new music style-rock and roll.
Question: The "field holler" is a kind of music that came from _ .
Options: (A) the American South. (B) Africa. (C) Chicago. (D) Asia.

Ex Output:
B

Ex Input:
Article: Some fish may contain harmful chemicals, which can be the result of both natural causes and water pollution. Mercury is a poisonous chemical, which occurs naturally in oceans and the Earth's crust , but also comes from man-made sources, such as farm chemicals, burning garbage, oil, coal, etc. Polyclilorinated bipheuyls (PCBs), a group of chemicals, can also be found in some fish. These man-made chemicals were used in many industries until 1977, when they were banned. PCBs were released or leaked into (lie tar and water and have bear transported around the globe. How do mercury and PCBs end up in fish and the food supply? When they arc released into the air, they attach themselves to particles .These particles settle on the ground and in the water and are eventually eater by micro-organisms. Small fish cat the micro-organisms, and large fish eat the small fish and on up the food chain. Because they can negatively affect your health, the U.S. Eavirotunental Protectioc Agency advises that kids younger than 15 years old avoid fish that cortain high levels of mercury and PCBs. These include shark, swordfish, king rrnackerel, and tilefish. There are also many types of fish that are good for you, but arc in danger of being wiped out because of ovcrfishing. Sonic are being fished in the wild so much that they cannot reproduce enough to survive.Others re being farmed in ways that are not environmentally friendly. These fish include red snapper.Atlantic salmon, bluefnn tuna. and king crab. Despite these problems, there are several fish that are both healthy and sustainable , such as Alaskan salmon, American catfish, Pacific cod, and several fans-raised fish and shellfish.
Question: Which of the following is true of PCBs according to the text?
Options: (A) They are transported by human beings around the globe. (B) They have been widely used in &c world since 1977. (C) They are hard to be cleared out from nature. (D) They arc a kind of man-made fish food.

Ex Output:
C