B, rice mainly provides starch and other sugars, fried pork slices, hairtail and tofu mainly provide protein, and vegetables and fruits mainly provide vitamins. This recipe is comprehensive and affordable, B is right;

C. Steamed buns and braised pork can provide protein, fat and other nutrients. Coke and chocolate have high sugar content, no fruits and vegetables, and can't provide vitamins. This recipe is unreasonable. C is wrong;

D, rice mainly provides starch and other sugars, lobster, grass carp, roast chicken and broth mainly provide protein, but it is not affordable, and the amount is too much to waste. Vegetables mainly provide vitamins.

So choose: B.