单选题 阅读下列短文，然后根据短文的内容从每小题的四个选择项中选出最佳的一项。
A　　In 2008, the United States Department of Agriculture (USDA) wanted to know if all the school lunches served to students were healthy.The answer was a big, fat NO!
The USDA found that most American schools served lunches with too much fat and salt.They also found that most of the fruits and vegedivs in the lunches came from cans（罐头）.Canned fruits and vegedivs are not as good as fresh ones.
The USDA gives schools food and money to make lunches.But schools make up their own menus.Some make healthy lunches.Most do not.Now the USDA wants all schools to serve more healthy lunches.They want schools to follow the USDA's guidelines for balanced（均衡）meals.
Mike Sanders, in charge of the USDA in 2008, said the USDA should teach school workers how to make healthier lunches."A good school lunch is just as important as a good textbook," Sanders said.He said that children also need to learn about healthy foods.
The USDA is working on a new program－Fresh Start.It will give schools more fresh fruits and vegedivs.Fresh Start will also help schools change their lunches to make them healthier.To find the best way to change lunches, the USDA held meetings with parents, school leaders, doctors, and cooks.
Children already eat healthy lunches at Chief Joseph School in North Saratoga, Oregon.They have whole-wheat bread with low-fat cheese, and low-fat milk.What are schools required to do to make the lunches healthy?（　　）