In October, Ubayd Steed, a sixth grader in Philadelphia, Pennsylvania, was taking a math test when he noticed a classmate looking at his paper. " I quickly turned my paper over," he said. Later that day, Ubayd met the cheater and told him not to do it again. Unfortunately, Ubayd' s experience is not unusual. Whether it's kids copying class -mates' answers during tests or friends sharing homework, cheating happens in schools every day. Experts say the behavior starts in the lower grades. Surveys show that one in three elementary students admits to cheating. Jacob Harder, a fourth grader in Ware, Massachusetts, has had classmates ask to copy his homework. "I wouldn't want to just tell them the answers," he says. So instead, he explains the task and encourages his classmates to do it themselves. But many kids find it hard to say no. "l hear from kids all the time, ' I can' t say no to a friend,'" says Eric Anderman, a professor at The Ohio State University who studies cheating in school. He says it' s important to say no from the start. "Then you _ , and the other kid gets the message," he says. Plus, he points out, "a real friend is not going to disown you because he or she couldn't copy your math homework." The kids doing the copying may feel they need to cheat to be accepted by other kids. And some students may cheat simply because others do. "If you' re in an atmosphere where cheating is common, you may think that if you don' t cheat, you' re at a disadvantage," says Michael Josephson, founder of the Josephson Institute of Ethics. But Josephson says students shouldn't think that way. "There are a lot of things kids do," he says. "You have to decide what kind of person you' re going to be." When school becomes too challenging, Anderman suggests going to the teacher rather than relying on the work of others. "It' s good to ask for help," he says. Ubayd' s experience serves as a(n)   _
explanation introduction comment background
Question: In October, Ubayd Steed, a sixth grader in Philadelphia, Pennsylvania, was taking a math test when he noticed a classmate looking at his paper. " I quickly turned my paper over," he said. Later that day, Ubayd met the cheater and told him not to do it again. Unfortunately, Ubayd' s experience is not unusual. Whether it's kids copying class -mates' answers during tests or friends sharing homework, cheating happens in schools every day. Experts say the behavior starts in the lower grades. Surveys show that one in three elementary students admits to cheating. Jacob Harder, a fourth grader in Ware, Massachusetts, has had classmates ask to copy his homework. "I wouldn't want to just tell them the answers," he says. So instead, he explains the task and encourages his classmates to do it themselves. But many kids find it hard to say no. "l hear from kids all the time, ' I can' t say no to a friend,'" says Eric Anderman, a professor at The Ohio State University who studies cheating in school. He says it' s important to say no from the start. "Then you _ , and the other kid gets the message," he says. Plus, he points out, "a real friend is not going to disown you because he or she couldn't copy your math homework." The kids doing the copying may feel they need to cheat to be accepted by other kids. And some students may cheat simply because others do. "If you' re in an atmosphere where cheating is common, you may think that if you don' t cheat, you' re at a disadvantage," says Michael Josephson, founder of the Josephson Institute of Ethics. But Josephson says students shouldn't think that way. "There are a lot of things kids do," he says. "You have to decide what kind of person you' re going to be." When school becomes too challenging, Anderman suggests going to the teacher rather than relying on the work of others. "It' s good to ask for help," he says. Ubayd' s experience serves as a(n)   _
A. explanation
B. introduction
C. comment
D. background
Answer: