甲公司因兼并乙公司，负有向丙公司付款20万元之义务；而此时依据甲、丙公司之间的合同，丙公司必须向甲公司提供价值20万元的彩电100台。现甲公司想抵销这笔债务，则：（）

A.经与乙公司协商一致后方可

B.可单方通知丙公司使债务抵销

C.自向乙公司发出抵销通知时，该笔债务抵销

D.自与丙公司就抵销问题达成协议后，该合同权利义务终止，当事人间不再负任何权利义务

Dietetics (营养学) is the application of the science of nutrition (营养) to the selection and preparation of foods, in health and disease. A dietitian is specially trained to give practical advice to individuals about their diets. He/she will have received training in a hospital and/or community setting as part of his/her course. Many dietitians are employed in the NHS (National Health Ser vice). They work with both healthy and sick people as well as their families. With patients who need special diets, dietitians use their scientific knowledge to provide practical information that is appropriate to the patient’s medical history and, lifestyle.

These days a large number of dietitians spend some or all of their time working in the community rather than in a hospital. Many of these have full conditions to apply for registration in public health nutrition as well as being registered dietitians (RD). In the community, the dietitian’s work is more about health education, although many also run clinics (诊所) for people who need specialists’ suggestions about the right diet. Dietitians also work in research, the food industry, government, the media and education. Information about part-time dietitians is available from the Freelance Dietitians Group of the British Dietetic Association.

It is necessary to have a degree (BSc or MSc) in nutrition and dietetics to work as a dietitian. The British Dietetic Association has information about qualifying as a dietitian. There exist undergraduate and postgraduate degrees for a qualified dietitian who has finished required courses.

This passage is mainly about().

A. dietetics

B. health education

C. British Dietetic Association

D. dietitians