A、Natural food. B、Organic food. C、Health food. D、The processing of food. CWhat is the main idea of the talk?

Health food is a general term applied to all kinds of food that are considered more healthful than the types of foods widely sold in supermarkets. For instance, whole grains, fried beaus, and corn oil are health foods. A narrower classification of health food is natural food, which is used to distinguish between types of the same food. Raw honey is a natural sweetener, whereas relined sugar is not. Fresh fruit is a natural food, but canned fruit, with sugars and other additives, is not. The most precise term of all and the narrowest classification within health food is organic food, which is used to describe food that has been grown on a particular kind of farm. Fruits and vegetables that are grown in gardens that are only treated with organic fertilizers, that are not sprayed with poisonous insecticides, and that are not refined after harvest, are organic foods. Meats, fish, dairy and poultry products from animals that are fed only organically-grown feed and that are not injected with hormones are organic foods.
    In choosing the type of food you eat, then, you have basically two choices: inorganic, processed foods, or organic, unprocessed foods. A wise decision should include investigation of the claims that processed foods contain chemicals, some of which ate proven to be poisonous, and that vitamin content is greatly reduced in processed foods.