单选题：Effects of Exercise on Elderly Diabetics (糖尿病人)　　Most older

Effects of Exercise on Elderly Diabetics (糖尿病人)　　Most older people with so-called type 2 diabetes (糖尿病人) could stop taking insulin(胰岛素) if they would do brisk (轻快的) exercise for 30 minutes just three times a week,according to new medical research results reported in a Copenhagen newspaper. Results from tests conducted on diabetics at the Copenhagen central hospital Rigshospitalet's Center for Muscle Research showed that physical exercise can boost the body's ability to make use of insulin by 30 per cent. This is equal to the effect most elderly diabetics get from their insulin medication (药物治疗) today.
　　Researchers had a group of non-diabetic men and a group of men with type 2
diabetes, all more than 60 years of age, exercise on bicycles six times a week for three months. After the three months the doctors measured how much sugar the test subjects' muscles could make use of as a measure for how well their insulin worked.
　　Associate Professor Dr Flemming Dela of the Muscle Research Center said the tests demonstrated that the exercising diabetics had made as good use of insulin as the healthy non-diabetic persons. "This means that the insulin works just as well for both groups. Physical exercise cannot cure people of diabetes, but it can eliminate almost all their symptoms. At the same time it can put off the point at which they have to begin taking insulin," Dela said.
　　Insulin is a hormone produced by the pancreas (胰腺), controlling sugar in the body and is used against diabetes.
　　Dela said that to achieve the desired effect diabetics need only exercise to the point where they begin to sweat, but that the activity has to be maintained since it wears off after five days without sufficient exercise.
　　Most diabetics realize that they have to watch their diet while remaining unaware of the importance of exercise, Dela added.What is the effect of exercise on elderly people with type 2 diabetes? A．It can help the body make better use of insuli
B．It can worsen their symptom
C．It can help them to eat mor
D．It can cure them of the diseas