题目内容：
About 70 million Americans are trying to lose weight. This is almost one out of21threepeople in the United States. Some people go on diets (节食). This22they eat less of certainfoods,especially fats and sugars.23people exercise with special equipment, take medicine,24even have surgery (手术). Losing weight is hard work, and it can also cost a lot of money. So25do so many people in the United States want to lose weight? Many people in the UnitedStates are26for looking young and pleasant. To many people,27good means being thin. Other people worry about their28. Many doctors say being overweight is unhealthy. But areAmericans really29?
Almost 30million Americans weigh at least 20 percent30than their proper weight.
31, the United States is the most overweight country in the world. "The stored32of adultAmericans weight 2,300 million pounds," said an American scientist. He said33off that storedenergy would produce enough power for 900,000 cars to go 12,000 miles.34losing weight ishard work, many people want to find a fast and easy35to take off fat.
根据以上内容,回答题.
第21答案是（ ） A．the
B．all
C．Every
D．these
参考答案：
答案解析：